diff --git a/src/org/thoughtcrime/securesms/components/ThumbnailView.java b/src/org/thoughtcrime/securesms/components/ThumbnailView.java
index b9a412c7c5..be2faf1971 100644
--- a/src/org/thoughtcrime/securesms/components/ThumbnailView.java
+++ b/src/org/thoughtcrime/securesms/components/ThumbnailView.java
@@ -160,9 +160,10 @@ public class ThumbnailView extends FrameLayout {
   }
 
   private GenericRequestBuilder buildThumbnailGlideRequest(@NonNull Slide slide, @NonNull MasterSecret masterSecret) {
+    @SuppressWarnings("ConstantConditions")
     DrawableRequestBuilder<DecryptableUri> builder = Glide.with(getContext()).load(new DecryptableUri(masterSecret, slide.getThumbnailUri()))
-                                                          .crossFade()
-                                                          .transform(new RoundedCorners(getContext(), true, radius, backgroundColorHint));
+                                                                             .crossFade()
+                                                                             .transform(new RoundedCorners(getContext(), true, radius, backgroundColorHint));
 
     if (slide.isInProgress()) return builder;
     else                      return builder.error(R.drawable.ic_missing_thumbnail_picture);
diff --git a/src/org/thoughtcrime/securesms/database/AttachmentDatabase.java b/src/org/thoughtcrime/securesms/database/AttachmentDatabase.java
index 7dae60b794..b2f5618e6d 100644
--- a/src/org/thoughtcrime/securesms/database/AttachmentDatabase.java
+++ b/src/org/thoughtcrime/securesms/database/AttachmentDatabase.java
@@ -129,7 +129,7 @@ public class AttachmentDatabase extends Database {
     try {
       InputStream generatedStream = thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, attachmentId)).get();
 
-      if (generatedStream == null) throw new IOException("No thumbnail stream available: " + attachmentId);
+      if (generatedStream == null) throw new FileNotFoundException("No thumbnail stream available: " + attachmentId);
       else                         return generatedStream;
     } catch (InterruptedException ie) {
       throw new AssertionError("interrupted");
diff --git a/src/org/thoughtcrime/securesms/mms/AttachmentStreamUriLoader.java b/src/org/thoughtcrime/securesms/mms/AttachmentStreamUriLoader.java
index 1c8abdb6cd..2db01844a0 100644
--- a/src/org/thoughtcrime/securesms/mms/AttachmentStreamUriLoader.java
+++ b/src/org/thoughtcrime/securesms/mms/AttachmentStreamUriLoader.java
@@ -2,6 +2,7 @@ package org.thoughtcrime.securesms.mms;
 
 import android.content.Context;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 
 import com.bumptech.glide.load.data.DataFetcher;
 import com.bumptech.glide.load.model.GenericLoaderFactory;
@@ -51,13 +52,29 @@ public class AttachmentStreamUriLoader implements StreamModelLoader<AttachmentMo
   }
 
   public static class AttachmentModel {
-    public File   attachment;
-    public byte[] key;
+    public @NonNull File   attachment;
+    public @NonNull byte[] key;
 
-    public AttachmentModel(File attachment, byte[] key) {
+    public AttachmentModel(@NonNull File attachment, @NonNull byte[] key) {
       this.attachment = attachment;
       this.key        = key;
     }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) return true;
+      if (o == null || getClass() != o.getClass()) return false;
+
+      AttachmentModel that = (AttachmentModel)o;
+
+      return attachment.equals(that.attachment);
+
+    }
+
+    @Override
+    public int hashCode() {
+      return attachment.hashCode();
+    }
   }
 }
 
diff --git a/src/org/thoughtcrime/securesms/mms/DecryptableStreamUriLoader.java b/src/org/thoughtcrime/securesms/mms/DecryptableStreamUriLoader.java
index bfb3a0a09e..b5fcdf3143 100644
--- a/src/org/thoughtcrime/securesms/mms/DecryptableStreamUriLoader.java
+++ b/src/org/thoughtcrime/securesms/mms/DecryptableStreamUriLoader.java
@@ -2,6 +2,7 @@ package org.thoughtcrime.securesms.mms;
 
 import android.content.Context;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 
 import com.bumptech.glide.load.data.DataFetcher;
 import com.bumptech.glide.load.model.GenericLoaderFactory;
@@ -48,13 +49,29 @@ public class DecryptableStreamUriLoader implements StreamModelLoader<Decryptable
   }
 
   public static class DecryptableUri {
-    public MasterSecret masterSecret;
-    public Uri          uri;
+    public @NonNull MasterSecret masterSecret;
+    public @NonNull Uri          uri;
 
-    public DecryptableUri(MasterSecret masterSecret, Uri uri) {
+    public DecryptableUri(@NonNull MasterSecret masterSecret, @NonNull Uri uri) {
       this.masterSecret = masterSecret;
       this.uri          = uri;
     }
+
+    @Override
+    public boolean equals(Object o) {
+      if (this == o) return true;
+      if (o == null || getClass() != o.getClass()) return false;
+
+      DecryptableUri that = (DecryptableUri)o;
+
+      return uri.equals(that.uri);
+
+    }
+
+    @Override
+    public int hashCode() {
+      return uri.hashCode();
+    }
   }
 }