diff --git a/src/org/thoughtcrime/securesms/database/MmsDatabase.java b/src/org/thoughtcrime/securesms/database/MmsDatabase.java
index ec504b9730..e74d71325b 100644
--- a/src/org/thoughtcrime/securesms/database/MmsDatabase.java
+++ b/src/org/thoughtcrime/securesms/database/MmsDatabase.java
@@ -165,8 +165,8 @@ public class MmsDatabase extends MessagingDatabase {
   };
 
   public static final ExecutorService slideResolver = org.thoughtcrime.securesms.util.Util.newSingleThreadedLifoExecutor();
-  private static final Map<Long, SoftReference<SlideDeck>> slideCache =
-      Collections.synchronizedMap(new LRUCache<Long, SoftReference<SlideDeck>>(20));
+  private static final Map<String, SoftReference<SlideDeck>> slideCache =
+      Collections.synchronizedMap(new LRUCache<String, SoftReference<SlideDeck>>(20));
 
   private final JobManager jobManager;
 
@@ -1045,7 +1045,7 @@ public class MmsDatabase extends MessagingDatabase {
       List<IdentityKeyMismatch> mismatches      = getMismatchedIdentities(mismatchDocument);
       List<NetworkFailure>      networkFailures = getFailures(networkDocument);
 
-      ListenableFutureTask<SlideDeck> slideDeck = getSlideDeck(masterSecret, id);
+      ListenableFutureTask<SlideDeck> slideDeck = getSlideDeck(masterSecret, dateReceived, id);
 
       return new MediaMmsMessageRecord(context, id, recipients, recipients.getPrimaryRecipient(),
                                        addressDeviceId, dateSent, dateReceived, receiptCount,
@@ -1109,9 +1109,10 @@ public class MmsDatabase extends MessagingDatabase {
     }
 
     private ListenableFutureTask<SlideDeck> getSlideDeck(final MasterSecret masterSecret,
+                                                         final long timestamp,
                                                          final long id)
     {
-      ListenableFutureTask<SlideDeck> future = getCachedSlideDeck(id);
+      ListenableFutureTask<SlideDeck> future = getCachedSlideDeck(timestamp, id);
 
       if (future != null) {
         return future;
@@ -1128,21 +1129,21 @@ public class MmsDatabase extends MessagingDatabase {
           SlideDeck    slideDeck    = new SlideDeck(context, masterSecret, body);
 
           if (!body.containsPushInProgress()) {
-            slideCache.put(id, new SoftReference<SlideDeck>(slideDeck));
+            slideCache.put(timestamp + "::" + id, new SoftReference<>(slideDeck));
           }
 
           return slideDeck;
         }
       };
 
-      future = new ListenableFutureTask<SlideDeck>(task);
+      future = new ListenableFutureTask<>(task);
       slideResolver.execute(future);
 
       return future;
     }
 
-    private ListenableFutureTask<SlideDeck> getCachedSlideDeck(final long id) {
-      SoftReference<SlideDeck> reference = slideCache.get(id);
+    private ListenableFutureTask<SlideDeck> getCachedSlideDeck(final long timestamp, final long id) {
+      SoftReference<SlideDeck> reference = slideCache.get(timestamp + "::" + id);
 
       if (reference != null) {
         final SlideDeck slideDeck = reference.get();
@@ -1155,7 +1156,7 @@ public class MmsDatabase extends MessagingDatabase {
             }
           };
 
-          ListenableFutureTask<SlideDeck> future = new ListenableFutureTask<SlideDeck>(task);
+          ListenableFutureTask<SlideDeck> future = new ListenableFutureTask<>(task);
           future.run();
 
           return future;
diff --git a/src/org/thoughtcrime/securesms/database/PartDatabase.java b/src/org/thoughtcrime/securesms/database/PartDatabase.java
index 9fcffdeb8f..f89ef49f99 100644
--- a/src/org/thoughtcrime/securesms/database/PartDatabase.java
+++ b/src/org/thoughtcrime/securesms/database/PartDatabase.java
@@ -79,6 +79,8 @@ public class PartDatabase extends Database {
   private static final String THUMBNAIL               = "thumbnail";
   private static final String ASPECT_RATIO            = "aspect_ratio";
 
+  private static final String ID_CONTENT_WHERE = ID + " = ? AND " + CONTENT_ID + " = ?";
+
   public static final String CREATE_TABLE = "CREATE TABLE " + TABLE_NAME + " (" + ID + " INTEGER PRIMARY KEY, " +
     MMS_ID + " INTEGER, " + SEQUENCE + " INTEGER DEFAULT 0, "                        +
     CONTENT_TYPE + " TEXT, " + NAME + " TEXT, " + CHARSET + " INTEGER, "             +
@@ -113,10 +115,10 @@ public class PartDatabase extends Database {
     super(context, databaseHelper);
   }
 
-  public InputStream getPartStream(MasterSecret masterSecret, long partId)
+  public InputStream getPartStream(MasterSecret masterSecret, long partId, byte[] contentId)
       throws FileNotFoundException
   {
-    return getDataStream(masterSecret, partId, DATA);
+    return getDataStream(masterSecret, partId, contentId, DATA);
   }
 
   public void updateFailedDownloadedPart(long messageId, long partId, PduPart part)
@@ -206,7 +208,7 @@ public class PartDatabase extends Database {
         cursor.close();
     }
 
-    database.delete(TABLE_NAME, MMS_ID + " = ?", new String[] {mmsId+""});
+    database.delete(TABLE_NAME, MMS_ID + " = ?", new String[] {mmsId + ""});
   }
 
   @SuppressWarnings("ResultOfMethodCallIgnored")
@@ -343,15 +345,17 @@ public class PartDatabase extends Database {
     return new EncryptingPartOutputStream(path, masterSecret);
   }
 
-  @VisibleForTesting InputStream getDataStream(MasterSecret masterSecret, long partId, String dataType)
+  @VisibleForTesting InputStream getDataStream(MasterSecret masterSecret, long partId, byte[] contentId, String dataType)
       throws FileNotFoundException
   {
     SQLiteDatabase database = databaseHelper.getReadableDatabase();
     Cursor         cursor   = null;
 
     try {
-      cursor = database.query(TABLE_NAME, new String[]{dataType}, ID_WHERE,
-                              new String[] {partId+""}, null, null, null);
+      cursor = database.query(TABLE_NAME, new String[]{dataType}, ID_CONTENT_WHERE,
+                              new String[] {String.valueOf(partId),
+                                            Util.toIsoString(contentId)},
+                              null, null, null);
 
       if (cursor != null && cursor.moveToFirst()) {
         if (cursor.isNull(0)) {
@@ -402,15 +406,15 @@ public class PartDatabase extends Database {
     }
   }
 
-  public InputStream getThumbnailStream(final MasterSecret masterSecret, final long partId) throws IOException {
+  public InputStream getThumbnailStream(MasterSecret masterSecret, long partId, byte[] contentId) throws IOException {
     Log.w(TAG, "getThumbnailStream(" + partId + ")");
-    final InputStream dataStream = getDataStream(masterSecret, partId, THUMBNAIL);
+    final InputStream dataStream = getDataStream(masterSecret, partId, contentId, THUMBNAIL);
     if (dataStream != null) {
       return dataStream;
     }
 
     try {
-      return thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId)).get();
+      return thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId, contentId)).get();
     } catch (InterruptedException ie) {
       throw new AssertionError("interrupted");
     } catch (ExecutionException ee) {
@@ -424,7 +428,7 @@ public class PartDatabase extends Database {
 
     getPartValues(part, cursor);
 
-    part.setDataUri(ContentUris.withAppendedId(PartAuthority.PART_CONTENT_URI, part.getId()));
+    part.setDataUri(PartAuthority.getPartUri(part.getId(), part.getContentId()));
 
     return part;
   }
@@ -454,7 +458,7 @@ public class PartDatabase extends Database {
       ThumbnailData data = new ThumbnailData(thumbnail);
       updatePartThumbnail(masterSecret, partId, part, data.toDataStream(), data.getAspectRatio());
     } else if (!part.isPendingPush()) {
-      thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId));
+      thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId, part.getContentId()));
     }
 
     return partId;
@@ -479,7 +483,7 @@ public class PartDatabase extends Database {
 
     database.update(TABLE_NAME, values, ID_WHERE, new String[]{partId+""});
 
-    thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId));
+    thumbnailExecutor.submit(new ThumbnailFetchCallable(masterSecret, partId, part.getContentId()));
 
     notifyConversationListeners(DatabaseFactory.getMmsDatabase(context).getThreadIdForMessage(messageId));
   }
@@ -534,11 +538,12 @@ public class PartDatabase extends Database {
 
   public static class ImageRecord {
     private long   partId;
+    private byte[] contentId;
     private String contentType;
     private String address;
     private long   date;
 
-    private ImageRecord(long partId, String contentType, String address, long date) {
+    private ImageRecord(long partId, byte[] contentId, String contentType, String address, long date) {
       this.partId      = partId;
       this.contentType = contentType;
       this.address     = address;
@@ -547,6 +552,7 @@ public class PartDatabase extends Database {
 
     public static ImageRecord from(Cursor cursor) {
       return new ImageRecord(cursor.getLong(cursor.getColumnIndexOrThrow(ID)),
+                             Util.toIsoBytes(cursor.getString(cursor.getColumnIndexOrThrow(CONTENT_ID))),
                              cursor.getString(cursor.getColumnIndexOrThrow(CONTENT_TYPE)),
                              cursor.getString(cursor.getColumnIndexOrThrow(MmsDatabase.ADDRESS)),
                              cursor.getLong(cursor.getColumnIndexOrThrow(MmsDatabase.NORMALIZED_DATE_RECEIVED)) * 1000);
@@ -569,22 +575,24 @@ public class PartDatabase extends Database {
     }
 
     public Uri getUri() {
-      return ContentUris.withAppendedId(PartAuthority.PART_CONTENT_URI, getPartId());
+      return PartAuthority.getPartUri(partId, contentId);
     }
   }
 
   @VisibleForTesting class ThumbnailFetchCallable implements Callable<InputStream> {
     private final MasterSecret masterSecret;
     private final long         partId;
+    private final byte[]       contentId;
 
-    public ThumbnailFetchCallable(MasterSecret masterSecret, long partId) {
+    public ThumbnailFetchCallable(MasterSecret masterSecret, long partId, byte[] contentId) {
       this.masterSecret = masterSecret;
       this.partId       = partId;
+      this.contentId    = contentId;
     }
 
     @Override
     public InputStream call() throws Exception {
-      final InputStream stream = getDataStream(masterSecret, partId, THUMBNAIL);
+      final InputStream stream = getDataStream(masterSecret, partId, contentId, THUMBNAIL);
       if (stream != null) {
         return stream;
       }
@@ -599,7 +607,8 @@ public class PartDatabase extends Database {
       } catch (BitmapDecodingException bde) {
         throw new IOException(bde);
       }
-      return getDataStream(masterSecret, partId, THUMBNAIL);
+
+      return getDataStream(masterSecret, partId, contentId, THUMBNAIL);
     }
   }
 }
diff --git a/src/org/thoughtcrime/securesms/mms/ImageSlide.java b/src/org/thoughtcrime/securesms/mms/ImageSlide.java
index 63e3a652c7..faf51a7b2a 100644
--- a/src/org/thoughtcrime/securesms/mms/ImageSlide.java
+++ b/src/org/thoughtcrime/securesms/mms/ImageSlide.java
@@ -46,7 +46,7 @@ public class ImageSlide extends Slide {
     if (!getPart().isPendingPush() && getPart().getDataUri() != null) {
       return isDraft()
              ? getPart().getDataUri()
-             : PartAuthority.getThumbnailUri(getPart().getId());
+             : PartAuthority.getThumbnailUri(getPart().getId(), part.getContentId());
     }
 
     return null;
diff --git a/src/org/thoughtcrime/securesms/mms/IncomingMediaMessage.java b/src/org/thoughtcrime/securesms/mms/IncomingMediaMessage.java
index bf92437727..4b8f13e22b 100644
--- a/src/org/thoughtcrime/securesms/mms/IncomingMediaMessage.java
+++ b/src/org/thoughtcrime/securesms/mms/IncomingMediaMessage.java
@@ -32,6 +32,10 @@ public class IncomingMediaMessage {
     this.body    = retreived.getBody();
     this.groupId = null;
     this.push    = false;
+
+    for (int i=0;i<body.getPartsNum();i++) {
+      body.getPart(i).setContentId(String.valueOf(System.currentTimeMillis()).getBytes());
+    }
   }
 
   public IncomingMediaMessage(MasterSecret masterSecret,
diff --git a/src/org/thoughtcrime/securesms/mms/PartAuthority.java b/src/org/thoughtcrime/securesms/mms/PartAuthority.java
index db237bafed..04387dfaad 100644
--- a/src/org/thoughtcrime/securesms/mms/PartAuthority.java
+++ b/src/org/thoughtcrime/securesms/mms/PartAuthority.java
@@ -9,6 +9,7 @@ import org.thoughtcrime.securesms.crypto.MasterSecret;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
 import org.thoughtcrime.securesms.database.PartDatabase;
 import org.thoughtcrime.securesms.providers.PartProvider;
+import org.thoughtcrime.securesms.util.Hex;
 
 import java.io.IOException;
 import java.io.InputStream;
@@ -17,8 +18,8 @@ public class PartAuthority {
 
   private static final String PART_URI_STRING   = "content://org.thoughtcrime.securesms/part";
   private static final String THUMB_URI_STRING  = "content://org.thoughtcrime.securesms/thumb";
-  public  static final Uri    PART_CONTENT_URI  = Uri.parse(PART_URI_STRING);
-  public  static final Uri    THUMB_CONTENT_URI = Uri.parse(THUMB_URI_STRING);
+  private static final Uri    PART_CONTENT_URI  = Uri.parse(PART_URI_STRING);
+  private static final Uri    THUMB_CONTENT_URI = Uri.parse(THUMB_URI_STRING);
 
   private static final int PART_ROW  = 1;
   private static final int THUMB_ROW = 2;
@@ -27,8 +28,8 @@ public class PartAuthority {
 
   static {
     uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
-    uriMatcher.addURI("org.thoughtcrime.securesms", "part/#", PART_ROW);
-    uriMatcher.addURI("org.thoughtcrime.securesms", "thumb/#", THUMB_ROW);
+    uriMatcher.addURI("org.thoughtcrime.securesms", "part/*/#", PART_ROW);
+    uriMatcher.addURI("org.thoughtcrime.securesms", "thumb/*/#", THUMB_ROW);
   }
 
   public static InputStream getPartStream(Context context, MasterSecret masterSecret, Uri uri)
@@ -39,9 +40,14 @@ public class PartAuthority {
 
     try {
       switch (match) {
-      case PART_ROW:  return partDatabase.getPartStream(masterSecret, ContentUris.parseId(uri));
-      case THUMB_ROW: return partDatabase.getThumbnailStream(masterSecret, ContentUris.parseId(uri));
-      default:        return context.getContentResolver().openInputStream(uri);
+      case PART_ROW:
+        PartUri partUri = new PartUri(uri);
+        return partDatabase.getPartStream(masterSecret, partUri.getId(), partUri.getContentId());
+      case THUMB_ROW:
+        partUri = new PartUri(uri);
+        return partDatabase.getThumbnailStream(masterSecret, partUri.getId(), partUri.getContentId());
+      default:
+        return context.getContentResolver().openInputStream(uri);
       }
     } catch (SecurityException se) {
       throw new IOException(se);
@@ -49,10 +55,17 @@ public class PartAuthority {
   }
 
   public static Uri getPublicPartUri(Uri uri) {
-    return ContentUris.withAppendedId(PartProvider.CONTENT_URI, ContentUris.parseId(uri));
+    PartUri partUri = new PartUri(uri);
+    return PartProvider.getContentUri(partUri.getId(), partUri.getContentId());
   }
 
-  public static Uri getThumbnailUri(long partId) {
-    return ContentUris.withAppendedId(THUMB_CONTENT_URI, partId);
+  public static Uri getPartUri(long partId, byte[] contentId) {
+    Uri uri = Uri.withAppendedPath(PART_CONTENT_URI, Hex.toStringCondensed(contentId));
+    return ContentUris.withAppendedId(uri, partId);
+  }
+
+  public static Uri getThumbnailUri(long partId, byte[] contentId) {
+    Uri uri = Uri.withAppendedPath(THUMB_CONTENT_URI, Hex.toStringCondensed(contentId));
+    return ContentUris.withAppendedId(uri, partId);
   }
 }
diff --git a/src/org/thoughtcrime/securesms/mms/PartUri.java b/src/org/thoughtcrime/securesms/mms/PartUri.java
new file mode 100644
index 0000000000..1bc0d81bde
--- /dev/null
+++ b/src/org/thoughtcrime/securesms/mms/PartUri.java
@@ -0,0 +1,30 @@
+package org.thoughtcrime.securesms.mms;
+
+import android.content.ContentUris;
+import android.net.Uri;
+
+import org.thoughtcrime.securesms.util.Hex;
+
+import java.io.IOException;
+
+public class PartUri {
+
+  private final Uri uri;
+
+  public PartUri(Uri uri) {
+    this.uri = uri;
+  }
+
+  public long getId() {
+    return ContentUris.parseId(uri);
+  }
+
+  public byte[] getContentId() {
+    try {
+      return Hex.fromStringCondensed(uri.getPathSegments().get(1));
+    } catch (IOException e) {
+      throw new AssertionError(e);
+    }
+  }
+
+}
diff --git a/src/org/thoughtcrime/securesms/providers/PartProvider.java b/src/org/thoughtcrime/securesms/providers/PartProvider.java
index 2d090836cd..db0a843fc2 100644
--- a/src/org/thoughtcrime/securesms/providers/PartProvider.java
+++ b/src/org/thoughtcrime/securesms/providers/PartProvider.java
@@ -17,6 +17,7 @@
 package org.thoughtcrime.securesms.providers;
 
 import android.content.ContentProvider;
+import android.content.ContentUris;
 import android.content.ContentValues;
 import android.content.UriMatcher;
 import android.database.Cursor;
@@ -26,7 +27,9 @@ import android.util.Log;
 
 import org.thoughtcrime.securesms.crypto.MasterSecret;
 import org.thoughtcrime.securesms.database.DatabaseFactory;
+import org.thoughtcrime.securesms.mms.PartUri;
 import org.thoughtcrime.securesms.service.KeyCachingService;
+import org.thoughtcrime.securesms.util.Hex;
 
 import java.io.File;
 import java.io.FileNotFoundException;
@@ -38,14 +41,14 @@ public class PartProvider extends ContentProvider {
   private static final String TAG = PartProvider.class.getSimpleName();
 
   private static final String CONTENT_URI_STRING = "content://org.thoughtcrime.provider.securesms/part";
-  public  static final Uri    CONTENT_URI        = Uri.parse(CONTENT_URI_STRING);
+  private static final Uri    CONTENT_URI        = Uri.parse(CONTENT_URI_STRING);
   private static final int    SINGLE_ROW         = 1;
 
   private static final UriMatcher uriMatcher;
 
   static {
     uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
-    uriMatcher.addURI("org.thoughtcrime.provider.securesms", "part/#", SINGLE_ROW);
+    uriMatcher.addURI("org.thoughtcrime.provider.securesms", "part/*/#", SINGLE_ROW);
   }
 
   @Override
@@ -54,8 +57,13 @@ public class PartProvider extends ContentProvider {
     return true;
   }
 
-  private File copyPartToTemporaryFile(MasterSecret masterSecret, long partId) throws IOException {
-    InputStream in        = DatabaseFactory.getPartDatabase(getContext()).getPartStream(masterSecret, partId);
+  public static Uri getContentUri(long partId, byte[] contentId) {
+    Uri uri = Uri.withAppendedPath(CONTENT_URI, Hex.toStringCondensed(contentId));
+    return ContentUris.withAppendedId(uri, partId);
+  }
+
+  private File copyPartToTemporaryFile(MasterSecret masterSecret, long partId, byte[] contentId) throws IOException {
+    InputStream in        = DatabaseFactory.getPartDatabase(getContext()).getPartStream(masterSecret, partId, contentId);
     File tmpDir           = getContext().getDir("tmp", 0);
     File tmpFile          = File.createTempFile("test", ".jpg", tmpDir);
     FileOutputStream fout = new FileOutputStream(tmpFile);
@@ -72,7 +80,7 @@ public class PartProvider extends ContentProvider {
   }
 
   @Override
-    public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
+  public ParcelFileDescriptor openFile(Uri uri, String mode) throws FileNotFoundException {
     MasterSecret masterSecret = KeyCachingService.getMasterSecret(getContext());
     Log.w(TAG, "openFile() called!");
 
@@ -85,12 +93,14 @@ public class PartProvider extends ContentProvider {
     case SINGLE_ROW:
       Log.w(TAG, "Parting out a single row...");
       try {
-        int partId               = Integer.parseInt(uri.getPathSegments().get(1));
-        File tmpFile             = copyPartToTemporaryFile(masterSecret, partId);
-        ParcelFileDescriptor pdf = ParcelFileDescriptor.open(tmpFile, ParcelFileDescriptor.MODE_READ_ONLY);
+        PartUri              partUri = new PartUri(uri);
+        File                 tmpFile = copyPartToTemporaryFile(masterSecret, partUri.getId(), partUri.getContentId());
+        ParcelFileDescriptor pdf     = ParcelFileDescriptor.open(tmpFile, ParcelFileDescriptor.MODE_READ_ONLY);
+
         if (!tmpFile.delete()) {
           Log.w(TAG, "Failed to delete temp file.");
         }
+
         return pdf;
       } catch (IOException ioe) {
         Log.w(TAG, ioe);
diff --git a/src/ws/com/google/android/mms/pdu/PduPart.java b/src/ws/com/google/android/mms/pdu/PduPart.java
index d94602fe90..c3ea683fbf 100644
--- a/src/ws/com/google/android/mms/pdu/PduPart.java
+++ b/src/ws/com/google/android/mms/pdu/PduPart.java
@@ -142,6 +142,7 @@ public class PduPart {
       */
      public PduPart() {
          mPartHeader = new HashMap<Integer, Object>();
+         setContentId(String.valueOf(System.currentTimeMillis()).getBytes());
      }
 
      public void setEncrypted(boolean isEncrypted) {