diff --git a/lib/shared/messages/multimedia-message-spec.js b/lib/shared/messages/multimedia-message-spec.js
--- a/lib/shared/messages/multimedia-message-spec.js
+++ b/lib/shared/messages/multimedia-message-spec.js
@@ -25,6 +25,7 @@
 import type {
   MediaMessageData,
   MediaMessageInfo,
+  MediaMessageServerDBContent,
   RawMediaMessageInfo,
 } from '../../types/messages/media';
 import type { RawUnsupportedMessageInfo } from '../../types/messages/unsupported';
@@ -60,6 +61,22 @@
       | RawMediaMessageInfo
       | RawImagesMessageInfo,
   ): string {
+    if (data.type === messageTypes.MULTIMEDIA) {
+      const mediaMessageContents: $ReadOnlyArray<MediaMessageServerDBContent> = data.media.map(
+        media => {
+          if (media.type === 'photo') {
+            return { type: 'photo', uploadID: media.id };
+          } else {
+            return {
+              type: 'video',
+              uploadID: media.id,
+              thumbnailUploadID: media.thumbnailID,
+            };
+          }
+        },
+      );
+      return JSON.stringify(mediaMessageContents);
+    }
     const mediaIDs = data.media.map(media => parseInt(media.id, 10));
     return JSON.stringify(mediaIDs);
   },