[android] display image attachments for conversation messages

briar-android/src/main/java/org/briarproject/briar/android/AndroidComponent.java

@@ -29,6 +29,7 @@ import org.briarproject.bramble.api.system.LocationUtils;
 import org.briarproject.bramble.plugin.tor.CircumventionProvider;
 import org.briarproject.briar.BriarCoreEagerSingletons;
 import org.briarproject.briar.BriarCoreModule;
+import org.briarproject.briar.android.conversation.glide.BriarModelLoader;
 import org.briarproject.briar.android.login.SignInReminderReceiver;
 import org.briarproject.briar.android.reporting.BriarReportSender;
 import org.briarproject.briar.android.view.TextInputView;
@@ -170,6 +171,8 @@ public interface AndroidComponent
 
 	void inject(TextInputView textInputView);
 
+	void inject(BriarModelLoader briarModelLoader);
+
 	// Eager singleton load
 	void inject(AppModule.EagerSingletons init);
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentController.java

@@ -0,0 +1,198 @@
+package org.briarproject.briar.android.conversation;
+
+import android.content.res.Resources;
+import android.graphics.BitmapFactory;
+import android.support.annotation.Nullable;
+import android.support.media.ExifInterface;
+
+import org.briarproject.bramble.api.Pair;
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.R;
+import org.briarproject.briar.api.messaging.Attachment;
+import org.briarproject.briar.api.messaging.AttachmentHeader;
+import org.briarproject.briar.api.messaging.MessagingManager;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Map;
+import java.util.concurrent.ConcurrentHashMap;
+import java.util.logging.Logger;
+
+import static android.support.media.ExifInterface.ORIENTATION_ROTATE_270;
+import static android.support.media.ExifInterface.ORIENTATION_ROTATE_90;
+import static android.support.media.ExifInterface.ORIENTATION_TRANSPOSE;
+import static android.support.media.ExifInterface.ORIENTATION_TRANSVERSE;
+import static android.support.media.ExifInterface.TAG_IMAGE_LENGTH;
+import static android.support.media.ExifInterface.TAG_IMAGE_WIDTH;
+import static android.support.media.ExifInterface.TAG_ORIENTATION;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logDuration;
+import static org.briarproject.bramble.util.LogUtils.logException;
+import static org.briarproject.bramble.util.LogUtils.now;
+
+@NotNullByDefault
+class AttachmentController {
+
+	private static final Logger LOG =
+			getLogger(AttachmentController.class.getName());
+
+	private final MessagingManager messagingManager;
+	private final int defaultSize;
+	private final int minWidth, maxWidth;
+	private final int minHeight, maxHeight;
+
+	private final Map<MessageId, List<AttachmentItem>> attachmentCache =
+			new ConcurrentHashMap<>();
+
+	AttachmentController(MessagingManager messagingManager, Resources res) {
+		this.messagingManager = messagingManager;
+		defaultSize =
+				res.getDimensionPixelSize(R.dimen.message_bubble_image_default);
+		minWidth = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_min_width);
+		maxWidth = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_max_width);
+		minHeight = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_min_height);
+		maxHeight = res.getDimensionPixelSize(
+				R.dimen.message_bubble_image_max_height);
+	}
+
+	void put(MessageId messageId, List<AttachmentItem> attachments) {
+		attachmentCache.put(messageId, attachments);
+	}
+
+	@Nullable
+	List<AttachmentItem> get(MessageId messageId) {
+		return attachmentCache.get(messageId);
+	}
+
+	@DatabaseExecutor
+	List<Pair<AttachmentHeader, Attachment>> getMessageAttachments(
+			List<AttachmentHeader> headers) throws DbException {
+		long start = now();
+		List<Pair<AttachmentHeader, Attachment>> attachments =
+				new ArrayList<>(headers.size());
+		for (AttachmentHeader h : headers) {
+			Attachment a =
+					messagingManager.getAttachment(h.getMessageId());
+			attachments.add(new Pair<>(h, a));
+		}
+		logDuration(LOG, "Loading attachment", start);
+		return attachments;
+	}
+
+	List<AttachmentItem> getAttachmentItems(
+			List<Pair<AttachmentHeader, Attachment>> attachments) {
+		List<AttachmentItem> items = new ArrayList<>(attachments.size());
+		for (Pair<AttachmentHeader, Attachment> a : attachments) {
+			AttachmentItem item =
+					getAttachmentItem(a.getFirst(), a.getSecond());
+			items.add(item);
+		}
+		return items;
+	}
+
+	private AttachmentItem getAttachmentItem(AttachmentHeader h, Attachment a) {
+		MessageId messageId = h.getMessageId();
+		Size size = new Size();
+
+		InputStream is = a.getStream();
+		is.mark(Integer.MAX_VALUE);
+		try {
+			// use exif to get size
+			if (h.getContentType().equals("image/jpeg")) {
+				size = getSizeFromExif(is);
+			}
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+		try {
+			// use BitmapFactory to get size
+			if (size.error) {
+				is.reset();
+				size = getSizeFromBitmap(is);
+			}
+			is.close();
+		} catch (IOException e) {
+			logException(LOG, WARNING, e);
+		}
+
+		// calculate thumbnail size
+		Size thumbnailSize = new Size(defaultSize, defaultSize);
+		if (!size.error) {
+			thumbnailSize = getThumbnailSize(size.width, size.height);
+		}
+		return new AttachmentItem(messageId, size.width, size.height,
+				thumbnailSize.width, thumbnailSize.height, size.error);
+	}
+
+	/**
+	 * Gets the size of a JPEG {@link InputStream} if EXIF info is available.
+	 */
+	private static Size getSizeFromExif(InputStream is)
+			throws IOException {
+		ExifInterface exif = new ExifInterface(is);
+		// these can return 0 independent of default value
+		int width = exif.getAttributeInt(TAG_IMAGE_WIDTH, 0);
+		int height = exif.getAttributeInt(TAG_IMAGE_LENGTH, 0);
+		if (width == 0 || height == 0) return new Size();
+		int orientation = exif.getAttributeInt(TAG_ORIENTATION, 0);
+		if (orientation == ORIENTATION_ROTATE_90 ||
+				orientation == ORIENTATION_ROTATE_270 ||
+				orientation == ORIENTATION_TRANSVERSE ||
+				orientation == ORIENTATION_TRANSPOSE) {
+			//noinspection SuspiciousNameCombination
+			return new Size(height, width);
+		}
+		return new Size(width, height);
+	}
+
+	/**
+	 * Gets the size of any image {@link InputStream}.
+	 */
+	private static Size getSizeFromBitmap(InputStream is) {
+		BitmapFactory.Options options = new BitmapFactory.Options();
+		options.inJustDecodeBounds = true;
+		BitmapFactory.decodeStream(is, null, options);
+		if (options.outWidth == -1 || options.outHeight == -1)
+			return new Size();
+		return new Size(options.outWidth, options.outHeight);
+	}
+
+	private Size getThumbnailSize(int width, int height) {
+		float widthPercentage = maxWidth / (float) width;
+		float heightPercentage = maxHeight / (float) height;
+		float scaleFactor = Math.min(widthPercentage, heightPercentage);
+		int thumbnailWidth = (int) (width * scaleFactor);
+		int thumbnailHeight = (int) (height * scaleFactor);
+		if (thumbnailWidth < minWidth) thumbnailWidth = minWidth;
+		if (thumbnailHeight < minHeight) thumbnailHeight = minHeight;
+		return new Size(thumbnailWidth, thumbnailHeight);
+	}
+
+	private static class Size {
+		private int width;
+		private int height;
+		private boolean error;
+
+		private Size(int width, int height) {
+			this.width = width;
+			this.height = height;
+			this.error = false;
+		}
+
+		private Size() {
+			this.width = 0;
+			this.height = 0;
+			this.error = true;
+		}
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/AttachmentItem.java

@@ -0,0 +1,51 @@
+package org.briarproject.briar.android.conversation;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+
+import javax.annotation.concurrent.Immutable;
+
+@Immutable
+@NotNullByDefault
+public class AttachmentItem {
+
+	private final MessageId messageId;
+	private final int width, height;
+	private final int thumbnailWidth, thumbnailHeight;
+	private final boolean hasError;
+
+	AttachmentItem(MessageId messageId, int width, int height,
+			int thumbnailWidth, int thumbnailHeight, boolean hasError) {
+		this.messageId = messageId;
+		this.width = width;
+		this.height = height;
+		this.thumbnailWidth = thumbnailWidth;
+		this.thumbnailHeight = thumbnailHeight;
+		this.hasError = hasError;
+	}
+
+	public MessageId getMessageId() {
+		return messageId;
+	}
+
+	int getWidth() {
+		return width;
+	}
+
+	int getHeight() {
+		return height;
+	}
+
+	int getThumbnailWidth() {
+		return thumbnailWidth;
+	}
+
+	int getThumbnailHeight() {
+		return thumbnailHeight;
+	}
+
+	boolean hasError() {
+		return hasError;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationActivity.java

@@ -24,6 +24,7 @@ import android.widget.TextView;
 import android.widget.Toast;
 
 import org.briarproject.bramble.api.FormatException;
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.contact.ContactId;
 import org.briarproject.bramble.api.contact.ContactManager;
 import org.briarproject.bramble.api.contact.event.ContactRemovedEvent;
@@ -51,6 +52,7 @@ import org.briarproject.briar.R;
 import org.briarproject.briar.android.activity.ActivityComponent;
 import org.briarproject.briar.android.activity.BriarActivity;
 import org.briarproject.briar.android.blog.BlogActivity;
+import org.briarproject.briar.android.conversation.ConversationVisitor.AttachmentCache;
 import org.briarproject.briar.android.conversation.ConversationVisitor.TextCache;
 import org.briarproject.briar.android.forum.ForumActivity;
 import org.briarproject.briar.android.introduction.IntroductionActivity;
@@ -69,6 +71,8 @@ import org.briarproject.briar.api.conversation.ConversationResponse;
 import org.briarproject.briar.api.conversation.event.ConversationMessageReceivedEvent;
 import org.briarproject.briar.api.forum.ForumSharingManager;
 import org.briarproject.briar.api.introduction.IntroductionManager;
+import org.briarproject.briar.api.messaging.Attachment;
+import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.MessagingManager;
 import org.briarproject.briar.api.messaging.PrivateMessage;
 import org.briarproject.briar.api.messaging.PrivateMessageFactory;
@@ -116,7 +120,7 @@ import static uk.co.samuelwall.materialtaptargetprompt.MaterialTapTargetPrompt.S
 @ParametersNotNullByDefault
 public class ConversationActivity extends BriarActivity
 		implements EventListener, ConversationListener, TextInputListener,
-		TextCache {
+		TextCache, AttachmentCache {
 
 	public static final String CONTACT_ID = "briar.CONTACT_ID";
 
@@ -134,6 +138,7 @@ public class ConversationActivity extends BriarActivity
 	Executor cryptoExecutor;
 
 	private final Map<MessageId, String> textCache = new ConcurrentHashMap<>();
+	private AttachmentController attachmentController;
 
 	private ConversationViewModel viewModel;
 	private ConversationVisitor visitor;
@@ -191,6 +196,7 @@ public class ConversationActivity extends BriarActivity
 		viewModel = ViewModelProviders.of(this, viewModelFactory)
 				.get(ConversationViewModel.class);
 		viewModel.setContactId(contactId);
+		attachmentController = viewModel.getAttachmentController();
 
 		setContentView(R.layout.activity_conversation);
 
@@ -217,7 +223,7 @@ public class ConversationActivity extends BriarActivity
 		setTransitionName(toolbarAvatar, getAvatarTransitionName(contactId));
 		setTransitionName(toolbarStatus, getBulbTransitionName(contactId));
 
-		visitor = new ConversationVisitor(this, this,
+		visitor = new ConversationVisitor(this, this, this,
 				viewModel.getContactDisplayName());
 		adapter = new ConversationAdapter(this, this);
 		list = findViewById(R.id.conversationView);
@@ -340,14 +346,30 @@ public class ConversationActivity extends BriarActivity
 					// If the latest header is a private message, eagerly load
 					// its text so we can set the scroll position correctly
 					ConversationMessageHeader latest = sorted.get(0);
-					if (latest instanceof PrivateMessageHeader &&
-							((PrivateMessageHeader) latest).hasText()) {
+					if (latest instanceof PrivateMessageHeader) {
 						MessageId id = latest.getId();
-						String text = textCache.get(id);
-						if (text == null) {
-							LOG.info("Eagerly loading text of latest message");
-							text = messagingManager.getMessageText(id);
-							textCache.put(id, text);
+						PrivateMessageHeader h = (PrivateMessageHeader) latest;
+						if (h.hasText()) {
+							String text = textCache.get(id);
+							if (text == null) {
+								LOG.info(
+										"Eagerly loading text of latest message");
+								text = messagingManager.getMessageText(id);
+								textCache.put(id, text);
+							}
+						}
+						if (!h.getAttachmentHeaders().isEmpty()) {
+							List<AttachmentItem> items =
+									attachmentController.get(id);
+							if (items == null) {
+								LOG.info(
+										"Eagerly loading image size for latest message");
+								items = attachmentController.getAttachmentItems(
+										attachmentController
+												.getMessageAttachments(
+														h.getAttachmentHeaders()));
+								attachmentController.put(id, items);
+							}
 						}
 					}
 				}
@@ -408,16 +430,40 @@ public class ConversationActivity extends BriarActivity
 	private void displayMessageText(MessageId m, String text) {
 		runOnUiThreadUnlessDestroyed(() -> {
 			textCache.put(m, text);
-			SparseArray<ConversationMessageItem> messages =
-					adapter.getMessageItems();
-			for (int i = 0; i < messages.size(); i++) {
-				ConversationItem item = messages.valueAt(i);
-				if (item.getId().equals(m)) {
-					item.setText(text);
-					adapter.notifyItemChanged(messages.keyAt(i));
-					list.scrollToPosition(adapter.getItemCount() - 1);
-					return;
-				}
+			Pair<Integer, ConversationMessageItem> pair =
+					adapter.getMessageItem(m);
+			if (pair != null) {
+				pair.getSecond().setText(text);
+				adapter.notifyItemChanged(pair.getFirst());
+				list.scrollToPosition(adapter.getItemCount() - 1);
+			}
+		});
+	}
+
+	private void loadMessageAttachments(MessageId messageId,
+			List<AttachmentHeader> headers) {
+		runOnDbThread(() -> {
+			try {
+				displayMessageAttachments(messageId,
+						attachmentController.getMessageAttachments(headers));
+			} catch (DbException e) {
+				logException(LOG, WARNING, e);
+			}
+		});
+	}
+
+	private void displayMessageAttachments(MessageId m,
+			List<Pair<AttachmentHeader, Attachment>> attachments) {
+		runOnUiThreadUnlessDestroyed(() -> {
+			List<AttachmentItem> items =
+					attachmentController.getAttachmentItems(attachments);
+			attachmentController.put(m, items);
+			Pair<Integer, ConversationMessageItem> pair =
+					adapter.getMessageItem(m);
+			if (pair != null) {
+				pair.getSecond().setAttachments(items);
+				adapter.notifyItemChanged(pair.getFirst());
+				list.scrollToPosition(adapter.getItemCount() - 1);
 			}
 		});
 	}
@@ -782,4 +828,13 @@ public class ConversationActivity extends BriarActivity
 		if (text == null) loadMessageText(m);
 		return text;
 	}
+
+	@Nullable
+	@Override
+	public List<AttachmentItem> getAttachmentItems(MessageId m,
+			List<AttachmentHeader> headers) {
+		List<AttachmentItem> attachments = attachmentController.get(m);
+		if (attachments == null) loadMessageAttachments(m, headers);
+		return attachments;
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationAdapter.java

@@ -7,7 +7,9 @@ import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
+import org.briarproject.bramble.api.Pair;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
 import org.briarproject.briar.R;
 import org.briarproject.briar.android.util.BriarAdapter;
 
@@ -98,16 +100,16 @@ class ConversationAdapter
 		return messages;
 	}
 
-	SparseArray<ConversationMessageItem> getMessageItems() {
-		SparseArray<ConversationMessageItem> messages = new SparseArray<>();
-
+	@Nullable
+	Pair<Integer, ConversationMessageItem> getMessageItem(MessageId messageId) {
 		for (int i = 0; i < items.size(); i++) {
 			ConversationItem item = items.get(i);
-			if (item instanceof ConversationMessageItem) {
-				messages.put(i, (ConversationMessageItem) item);
+			if (item instanceof ConversationMessageItem &&
+					item.getId().equals(messageId)) {
+				return new Pair<>(i, (ConversationMessageItem) item);
 			}
 		}
-		return messages;
+		return null;
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationItemViewHolder.java

@@ -3,9 +3,9 @@ package org.briarproject.briar.android.conversation;
 import android.support.annotation.CallSuper;
 import android.support.annotation.Nullable;
 import android.support.annotation.UiThread;
+import android.support.constraint.ConstraintLayout;
 import android.support.v7.widget.RecyclerView.ViewHolder;
 import android.view.View;
-import android.view.ViewGroup;
 import android.widget.TextView;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
@@ -18,11 +18,11 @@ import static org.briarproject.briar.android.util.UiUtils.formatDate;
 @NotNullByDefault
 abstract class ConversationItemViewHolder extends ViewHolder {
 
-	protected final ViewGroup layout;
+	protected final ConstraintLayout layout;
 	@Nullable
 	private final OutItemViewHolder outViewHolder;
 	private final TextView text;
-	private final TextView time;
+	protected final TextView time;
 
 	ConversationItemViewHolder(View v, boolean isIncoming) {
 		super(v);

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationMessageItem.java

@@ -1,9 +1,9 @@
 package org.briarproject.briar.android.conversation;
 
 import android.support.annotation.LayoutRes;
+import android.support.annotation.Nullable;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
-import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 
 import java.util.List;
@@ -14,15 +14,22 @@ import javax.annotation.concurrent.NotThreadSafe;
 @NotNullByDefault
 class ConversationMessageItem extends ConversationItem {
 
-	private final List<AttachmentHeader> attachments;
+	@Nullable
+	private List<AttachmentItem> attachments;
 
-	ConversationMessageItem(@LayoutRes int layoutRes, PrivateMessageHeader h) {
+	ConversationMessageItem(@LayoutRes int layoutRes, PrivateMessageHeader h,
+			@Nullable List<AttachmentItem> attachments) {
 		super(layoutRes, h);
-		this.attachments = h.getAttachmentHeaders();
+		this.attachments = attachments;
 	}
 
-	List<AttachmentHeader> getAttachments() {
+	@Nullable
+	List<AttachmentItem> getAttachments() {
 		return attachments;
 	}
 
+	void setAttachments(List<AttachmentItem> attachments) {
+		this.attachments = attachments;
+	}
+
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationMessageViewHolder.java

@@ -1,18 +1,165 @@
 package org.briarproject.briar.android.conversation;
 
+import android.graphics.Bitmap;
+import android.support.annotation.DrawableRes;
 import android.support.annotation.UiThread;
+import android.support.constraint.ConstraintSet;
+import android.support.v4.content.ContextCompat;
 import android.view.View;
+import android.view.ViewGroup;
+import android.widget.ImageView;
+
+import com.bumptech.glide.load.MultiTransformation;
+import com.bumptech.glide.load.Transformation;
+import com.bumptech.glide.load.resource.bitmap.CenterCrop;
 
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.R;
+import org.briarproject.briar.android.conversation.glide.GlideApp;
+
+import jp.wasabeef.glide.transformations.RoundedCornersTransformation;
+
+import static com.bumptech.glide.load.engine.DiskCacheStrategy.NONE;
+import static com.bumptech.glide.load.resource.drawable.DrawableTransitionOptions.withCrossFade;
+import static jp.wasabeef.glide.transformations.RoundedCornersTransformation.CornerType.BOTTOM;
+import static jp.wasabeef.glide.transformations.RoundedCornersTransformation.CornerType.TOP_LEFT;
+import static jp.wasabeef.glide.transformations.RoundedCornersTransformation.CornerType.TOP_RIGHT;
 
 @UiThread
 @NotNullByDefault
 class ConversationMessageViewHolder extends ConversationItemViewHolder {
 
-	// image support will be added here (#1242)
+	@DrawableRes
+	private static final int errorRes = R.drawable.ic_image_broken;
+
+	private final ImageView imageView;
+	private final ViewGroup statusLayout;
+	private final int timeColor, timeColorBubble;
+	private final int radiusBig, radiusSmall;
+	private final ConstraintSet textConstraints = new ConstraintSet();
+	private final ConstraintSet imageConstraints = new ConstraintSet();
+	private final ConstraintSet imageTextConstraints = new ConstraintSet();
 
 	ConversationMessageViewHolder(View v, boolean isIncoming) {
 		super(v, isIncoming);
+		imageView = v.findViewById(R.id.imageView);
+		statusLayout = v.findViewById(R.id.statusLayout);
+		radiusBig = v.getContext().getResources()
+				.getDimensionPixelSize(R.dimen.message_bubble_radius_big);
+		radiusSmall = v.getContext().getResources()
+				.getDimensionPixelSize(R.dimen.message_bubble_radius_small);
+
+		// remember original status text color
+		timeColor = time.getCurrentTextColor();
+		timeColorBubble =
+				ContextCompat.getColor(v.getContext(), R.color.briar_white);
+
+		// clone constraint sets from layout files
+		textConstraints
+				.clone(v.getContext(), R.layout.list_item_conversation_msg_in);
+		imageConstraints.clone(v.getContext(),
+				R.layout.list_item_conversation_msg_image);
+		imageTextConstraints.clone(v.getContext(),
+				R.layout.list_item_conversation_msg_image_text);
+
+		// in/out are different layouts, so we need to do this only once
+		textConstraints
+				.setHorizontalBias(R.id.statusLayout, isIncoming() ? 1 : 0);
+		imageConstraints
+				.setHorizontalBias(R.id.statusLayout, isIncoming() ? 1 : 0);
+		imageTextConstraints
+				.setHorizontalBias(R.id.statusLayout, isIncoming() ? 1 : 0);
+	}
+
+	@Override
+	void bind(ConversationItem conversationItem,
+			ConversationListener listener) {
+		super.bind(conversationItem, listener);
+		ConversationMessageItem item =
+				(ConversationMessageItem) conversationItem;
+		if (item.getAttachments() == null || item.getAttachments().isEmpty()) {
+			bindTextItem();
+		} else {
+			bindImageItem(item);
+		}
+	}
+
+	private void bindTextItem() {
+		clearImage();
+		statusLayout.setBackgroundResource(0);
+		// also reset padding (the background drawable defines some)
+		statusLayout.setPadding(0, 0, 0, 0);
+		time.setTextColor(timeColor);
+		textConstraints.applyTo(layout);
+	}
+
+	private void bindImageItem(ConversationMessageItem item) {
+		// TODO show more than just the first image
+		AttachmentItem attachment = item.getAttachments().get(0);
+
+		ConstraintSet constraintSet;
+		if (item.getText() == null) {
+			statusLayout
+					.setBackgroundResource(R.drawable.msg_status_bubble);
+			time.setTextColor(timeColorBubble);
+			constraintSet = imageConstraints;
+		} else {
+			statusLayout.setBackgroundResource(0);
+			// also reset padding (the background drawable defines some)
+			statusLayout.setPadding(0, 0, 0, 0);
+			time.setTextColor(timeColor);
+			constraintSet = imageTextConstraints;
+		}
+
+		// apply image size constraints, so glides picks them up for scaling
+		int width = attachment.getThumbnailWidth();
+		int height = attachment.getThumbnailHeight();
+		constraintSet.constrainWidth(R.id.imageView, width);
+		constraintSet.constrainHeight(R.id.imageView, height);
+		constraintSet.applyTo(layout);
+
+		if (attachment.hasError()) {
+			clearImage();
+			imageView.setImageResource(errorRes);
+		} else {
+			loadImage(item, attachment);
+		}
+	}
+
+	private void clearImage() {
+		GlideApp.with(imageView)
+				.clear(imageView);
+	}
+
+	private void loadImage(ConversationMessageItem item,
+			AttachmentItem attachment) {
+		// these transformations can be optimized by writing our own
+		Transformation<Bitmap> transformation;
+		if (item.getText() == null) {
+			transformation = new MultiTransformation<>(new CenterCrop(),
+					new RoundedCornersTransformation(radiusSmall, 0,
+							isIncoming() ? TOP_LEFT : TOP_RIGHT),
+					new RoundedCornersTransformation(radiusBig, 0,
+							isIncoming() ? TOP_RIGHT : TOP_LEFT),
+					new RoundedCornersTransformation(radiusBig, 0, BOTTOM)
+			);
+		} else {
+			transformation = new MultiTransformation<>(new CenterCrop(),
+					new RoundedCornersTransformation(radiusSmall, 0,
+							isIncoming() ? TOP_LEFT : TOP_RIGHT),
+					new RoundedCornersTransformation(radiusBig, 0,
+							isIncoming() ? TOP_RIGHT : TOP_LEFT)
+			);
+		}
+
+		GlideApp.with(imageView)
+				.load(attachment)
+				.diskCacheStrategy(NONE)
+				.error(errorRes)
+				.transform(transformation)
+				.transition(withCrossFade())
+				.into(imageView)
+				.waitForLayout();
 	}
 
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationViewModel.java

@@ -16,6 +16,7 @@ import org.briarproject.bramble.api.db.NoSuchContactException;
 import org.briarproject.bramble.api.identity.AuthorId;
 import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
 import org.briarproject.briar.android.util.UiUtils;
+import org.briarproject.briar.api.messaging.MessagingManager;
 
 import java.util.concurrent.Executor;
 import java.util.logging.Logger;
@@ -38,6 +39,7 @@ public class ConversationViewModel extends AndroidViewModel {
 	@DatabaseExecutor
 	private final Executor dbExecutor;
 	private final ContactManager contactManager;
+	private final AttachmentController attachmentController;
 
 	@Nullable
 	private ContactId contactId = null;
@@ -52,10 +54,12 @@ public class ConversationViewModel extends AndroidViewModel {
 	@Inject
 	ConversationViewModel(Application application,
 			@DatabaseExecutor Executor dbExecutor,
-			ContactManager contactManager) {
+			ContactManager contactManager, MessagingManager messagingManager) {
 		super(application);
 		this.dbExecutor = dbExecutor;
 		this.contactManager = contactManager;
+		this.attachmentController = new AttachmentController(messagingManager,
+				application.getResources());
 		contactDeleted.setValue(false);
 	}
 
@@ -96,6 +100,10 @@ public class ConversationViewModel extends AndroidViewModel {
 		});
 	}
 
+	AttachmentController getAttachmentController() {
+		return attachmentController;
+	}
+
 	LiveData<Contact> getContact() {
 		return contact;
 	}

briar-android/src/main/java/org/briarproject/briar/android/conversation/ConversationVisitor.java

@@ -14,12 +14,16 @@ import org.briarproject.briar.api.forum.ForumInvitationRequest;
 import org.briarproject.briar.api.forum.ForumInvitationResponse;
 import org.briarproject.briar.api.introduction.IntroductionRequest;
 import org.briarproject.briar.api.introduction.IntroductionResponse;
+import org.briarproject.briar.api.messaging.AttachmentHeader;
 import org.briarproject.briar.api.messaging.PrivateMessageHeader;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationRequest;
 import org.briarproject.briar.api.privategroup.invitation.GroupInvitationResponse;
 
+import java.util.List;
+
 import javax.annotation.Nullable;
 
+import static java.util.Collections.emptyList;
 import static org.briarproject.briar.android.conversation.ConversationRequestItem.RequestType.BLOG;
 import static org.briarproject.briar.android.conversation.ConversationRequestItem.RequestType.FORUM;
 import static org.briarproject.briar.android.conversation.ConversationRequestItem.RequestType.GROUP;
@@ -33,24 +37,33 @@ class ConversationVisitor implements
 
 	private final Context ctx;
 	private final TextCache textCache;
+	private final AttachmentCache attachmentCache;
 	private final LiveData<String> contactName;
 
 	ConversationVisitor(Context ctx, TextCache textCache,
-			LiveData<String> contactName) {
+			AttachmentCache attachmentCache, LiveData<String> contactName) {
 		this.ctx = ctx;
 		this.textCache = textCache;
+		this.attachmentCache = attachmentCache;
 		this.contactName = contactName;
 	}
 
 	@Override
 	public ConversationItem visitPrivateMessageHeader(PrivateMessageHeader h) {
 		ConversationItem item;
+		List<AttachmentItem> attachments;
+		if (h.getAttachmentHeaders().isEmpty()) {
+			attachments = emptyList();
+		} else {
+			attachments = attachmentCache
+					.getAttachmentItems(h.getId(), h.getAttachmentHeaders());
+		}
 		if (h.isLocal()) {
 			item = new ConversationMessageItem(
-					R.layout.list_item_conversation_msg_out, h);
+					R.layout.list_item_conversation_msg_out, h, attachments);
 		} else {
 			item = new ConversationMessageItem(
-					R.layout.list_item_conversation_msg_in, h);
+					R.layout.list_item_conversation_msg_in, h, attachments);
 		}
 		if (h.hasText()) {
 			String text = textCache.getText(h.getId());
@@ -279,4 +292,10 @@ class ConversationVisitor implements
 		@Nullable
 		String getText(MessageId m);
 	}
+
+	interface AttachmentCache {
+		@Nullable
+		List<AttachmentItem> getAttachmentItems(MessageId m,
+				List<AttachmentHeader> headers);
+	}
 }

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarDataFetcher.java

@@ -0,0 +1,96 @@
+package org.briarproject.briar.android.conversation.glide;
+
+import android.support.annotation.Nullable;
+
+import com.bumptech.glide.Priority;
+import com.bumptech.glide.load.DataSource;
+import com.bumptech.glide.load.data.DataFetcher;
+
+import org.briarproject.bramble.api.db.DatabaseExecutor;
+import org.briarproject.bramble.api.db.DbException;
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.bramble.api.sync.MessageId;
+import org.briarproject.briar.android.conversation.AttachmentItem;
+import org.briarproject.briar.api.messaging.MessagingManager;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.concurrent.Executor;
+import java.util.logging.Logger;
+
+import javax.inject.Inject;
+
+import static com.bumptech.glide.load.DataSource.LOCAL;
+import static java.util.Objects.requireNonNull;
+import static java.util.logging.Level.WARNING;
+import static java.util.logging.Logger.getLogger;
+import static org.briarproject.bramble.util.LogUtils.logException;
+
+@NotNullByDefault
+class BriarDataFetcher implements DataFetcher<InputStream> {
+
+	private final static Logger LOG =
+			getLogger(BriarDataFetcher.class.getName());
+
+	private final MessagingManager messagingManager;
+	@DatabaseExecutor
+	private final Executor dbExecutor;
+
+	@Nullable
+	private AttachmentItem attachment;
+	@Nullable
+	private volatile InputStream inputStream;
+
+	@Inject
+	public BriarDataFetcher(MessagingManager messagingManager,
+			@DatabaseExecutor Executor dbExecutor) {
+		this.messagingManager = messagingManager;
+		this.dbExecutor = dbExecutor;
+	}
+
+	@Override
+	public void loadData(Priority priority,
+			DataCallback<? super InputStream> callback) {
+		MessageId id = requireNonNull(attachment).getMessageId();
+		dbExecutor.execute(() -> {
+			try {
+				inputStream = messagingManager.getAttachment(id).getStream();
+				callback.onDataReady(inputStream);
+			} catch (DbException e) {
+				callback.onLoadFailed(e);
+			}
+		});
+	}
+
+	@Override
+	public void cleanup() {
+		final InputStream stream = inputStream;
+		if (stream != null) {
+			try {
+				stream.close();
+			} catch (IOException e) {
+				logException(LOG, WARNING, e);
+			}
+		}
+	}
+
+	@Override
+	public void cancel() {
+		// does it make sense to cancel a database load?
+	}
+
+	@Override
+	public Class<InputStream> getDataClass() {
+		return InputStream.class;
+	}
+
+	@Override
+	public DataSource getDataSource() {
+		return LOCAL;
+	}
+
+	public void setAttachment(AttachmentItem attachment) {
+		this.attachment = attachment;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarGlideModule.java

@@ -0,0 +1,43 @@
+package org.briarproject.briar.android.conversation.glide;
+
+import android.content.Context;
+
+import com.bumptech.glide.Glide;
+import com.bumptech.glide.GlideBuilder;
+import com.bumptech.glide.Registry;
+import com.bumptech.glide.annotation.GlideModule;
+import com.bumptech.glide.module.AppGlideModule;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.BriarApplication;
+import org.briarproject.briar.android.conversation.AttachmentItem;
+
+import java.io.InputStream;
+
+import static android.util.Log.DEBUG;
+import static android.util.Log.WARN;
+import static org.briarproject.briar.android.TestingConstants.IS_DEBUG_BUILD;
+
+@GlideModule
+@NotNullByDefault
+public final class BriarGlideModule extends AppGlideModule {
+
+	@Override
+	public void registerComponents(Context context, Glide glide,
+			Registry registry) {
+		BriarModelLoaderFactory factory =
+				new BriarModelLoaderFactory((BriarApplication) context);
+		registry.prepend(AttachmentItem.class, InputStream.class, factory);
+	}
+
+	@Override
+	public void applyOptions(Context context, GlideBuilder builder) {
+		builder.setLogLevel(IS_DEBUG_BUILD ? DEBUG : WARN);
+	}
+
+	@Override
+	public boolean isManifestParsingEnabled() {
+		return false;
+	}
+
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarModelLoader.java

@@ -0,0 +1,44 @@
+package org.briarproject.briar.android.conversation.glide;
+
+
+import com.bumptech.glide.load.Options;
+import com.bumptech.glide.load.model.ModelLoader;
+import com.bumptech.glide.signature.ObjectKey;
+
+import org.briarproject.bramble.api.nullsafety.MethodsNotNullByDefault;
+import org.briarproject.bramble.api.nullsafety.ParametersNotNullByDefault;
+import org.briarproject.briar.android.BriarApplication;
+import org.briarproject.briar.android.conversation.AttachmentItem;
+
+import java.io.InputStream;
+
+import javax.inject.Inject;
+
+@MethodsNotNullByDefault
+@ParametersNotNullByDefault
+public final class BriarModelLoader
+		implements ModelLoader<AttachmentItem, InputStream> {
+
+	private final BriarApplication app;
+
+	@Inject
+	BriarDataFetcher dataFetcher;
+
+	public BriarModelLoader(BriarApplication app) {
+		this.app = app;
+	}
+
+	@Override
+	public LoadData<InputStream> buildLoadData(AttachmentItem model, int width,
+			int height, Options options) {
+		app.getApplicationComponent().inject(this);
+		ObjectKey key = new ObjectKey(model.getMessageId());
+		dataFetcher.setAttachment(model);
+		return new LoadData<>(key, dataFetcher);
+	}
+
+	@Override
+	public boolean handles(AttachmentItem model) {
+		return true;
+	}
+}

briar-android/src/main/java/org/briarproject/briar/android/conversation/glide/BriarModelLoaderFactory.java

@@ -0,0 +1,34 @@
+package org.briarproject.briar.android.conversation.glide;
+
+import com.bumptech.glide.load.model.ModelLoader;
+import com.bumptech.glide.load.model.ModelLoaderFactory;
+import com.bumptech.glide.load.model.MultiModelLoaderFactory;
+
+import org.briarproject.bramble.api.nullsafety.NotNullByDefault;
+import org.briarproject.briar.android.BriarApplication;
+import org.briarproject.briar.android.conversation.AttachmentItem;
+
+import java.io.InputStream;
+
+@NotNullByDefault
+class BriarModelLoaderFactory
+		implements ModelLoaderFactory<AttachmentItem, InputStream> {
+
+	private final BriarApplication app;
+
+	public BriarModelLoaderFactory(BriarApplication app) {
+		this.app = app;
+	}
+
+	@Override
+	public ModelLoader<AttachmentItem, InputStream> build(
+			MultiModelLoaderFactory multiFactory) {
+		return new BriarModelLoader(app);
+	}
+
+	@Override
+	public void teardown() {
+		// noop
+	}
+
+}