diff --git a/js/views/attachment_view.js b/js/views/attachment_view.js
index c19e4ebf44..84d7fab35e 100644
--- a/js/views/attachment_view.js
+++ b/js/views/attachment_view.js
@@ -109,7 +109,8 @@
       }
 
       const props = {
-        imageURL: this.objectUrl,
+        objectURL: this.objectUrl,
+        contentType: this.model.contentType,
         onSave: () => this.saveFile(),
         // implicit: `close`
       };
diff --git a/js/views/conversation_view.js b/js/views/conversation_view.js
index 956a9ede16..aa5c738ec5 100644
--- a/js/views/conversation_view.js
+++ b/js/views/conversation_view.js
@@ -600,25 +600,28 @@
       const media = await loadMessages(rawMedia);
 
       const saveAttachment = async ({ message } = {}) => {
-        const loadedMessage = await Signal.Migrations.loadMessage(message);
-        const attachment = loadedMessage.attachments[0];
-        const timestamp = loadedMessage.received_at;
+        const attachment = message.attachments[0];
+        const timestamp = message.received_at;
         Signal.Types.AttachmentTS.save({ attachment, timestamp });
       };
 
       const onItemClick = async ({ message, type }) => {
+        const loadedMessage = Signal.Components.Types.Message
+          .withObjectURL(await Signal.Migrations.loadMessage(message));
         switch (type) {
           case 'documents': {
-            saveAttachment({ message });
+            saveAttachment({ message: loadedMessage });
             break;
           }
 
           case 'media': {
+            const attachment = loadedMessage.attachments[0];
             this.lightboxView = new Whisper.ReactWrapperView({
               Component: Signal.Components.Lightbox,
               props: {
-                imageURL: message.objectURL,
-                onSave: () => saveAttachment({ message }),
+                objectURL: loadedMessage.objectURL,
+                contentType: attachment.contentType,
+                onSave: () => saveAttachment({ message: loadedMessage }),
               },
               onClose: () => Signal.Backbone.Views.Lightbox.hide(),
             });
diff --git a/ts/components/Lightbox.md b/ts/components/Lightbox.md
index a5fbd148e6..4bc11546d2 100644
--- a/ts/components/Lightbox.md
+++ b/ts/components/Lightbox.md
@@ -3,7 +3,8 @@ const noop = () => {};
 
 <div style={{position: 'relative', width: '100%', height: 500}}>
   <Lightbox
-    imageURL="https://placekitten.com/800/600"
+    objectURL="https://placekitten.com/800/600"
+    contentType="image/jpeg"
     onNext={noop}
     onPrevious={noop}
     onSave={noop}
diff --git a/ts/components/Lightbox.tsx b/ts/components/Lightbox.tsx
index 993f6ebeb7..8121d7ec52 100644
--- a/ts/components/Lightbox.tsx
+++ b/ts/components/Lightbox.tsx
@@ -4,13 +4,18 @@
 import React from 'react';
 
 import classNames from 'classnames';
+import is from '@sindresorhus/is';
+
+import * as GoogleChrome from '../util/GoogleChrome';
+import * as MIME from '../types/MIME';
 
 interface Props {
   close: () => void;
-  imageURL?: string;
+  objectURL: string;
+  contentType: MIME.MIMEType | undefined;
   onNext?: () => void;
   onPrevious?: () => void;
-  onSave: () => void;
+  onSave?: () => void;
 }
 
 const styles = {
@@ -67,7 +72,7 @@ export class Lightbox extends React.Component<Props, {}> {
   }
 
   public render() {
-    const { imageURL } = this.props;
+    const { contentType, objectURL } = this.props;
     return (
       <div
         style={styles.container}
@@ -75,11 +80,9 @@ export class Lightbox extends React.Component<Props, {}> {
         ref={this.setContainerRef}
       >
         <div style={styles.objectContainer}>
-          <img
-            style={styles.image}
-            src={imageURL}
-            onClick={this.onImageClick}
-          />
+          {!is.undefined(contentType)
+            ? this.renderObject({ objectURL, contentType })
+            : null}
         </div>
         <div style={styles.controls}>
           <IconButton type="close" onClick={this.onClose} />
@@ -97,6 +100,38 @@ export class Lightbox extends React.Component<Props, {}> {
     );
   }
 
+  private renderObject = ({
+    objectURL,
+    contentType,
+  }: {
+    objectURL: string;
+    contentType: MIME.MIMEType;
+  }) => {
+    const isImage = GoogleChrome.isImageTypeSupported(contentType);
+    if (isImage) {
+      return (
+        <img
+          style={styles.image}
+          src={objectURL}
+          onClick={this.onObjectClick}
+        />
+      );
+    }
+
+    const isVideo = GoogleChrome.isVideoTypeSupported(contentType);
+    if (isVideo) {
+      return (
+        <video controls>
+          <source src={objectURL} />
+        </video>
+      );
+    }
+
+    // tslint:disable-next-line no-console
+    console.log('Lightbox: Unexpected content type', { contentType });
+    return null;
+  };
+
   private setContainerRef = (value: HTMLDivElement) => {
     this.containerRef = value;
   };
@@ -125,7 +160,7 @@ export class Lightbox extends React.Component<Props, {}> {
     this.onClose();
   };
 
-  private onImageClick = (event: React.MouseEvent<HTMLImageElement>) => {
+  private onObjectClick = (event: React.MouseEvent<HTMLImageElement>) => {
     event.stopPropagation();
     this.onClose();
   };
diff --git a/ts/components/conversation/media-gallery/types/Message.tsx b/ts/components/conversation/media-gallery/types/Message.tsx
index 73431ec59a..4b47504bd7 100644
--- a/ts/components/conversation/media-gallery/types/Message.tsx
+++ b/ts/components/conversation/media-gallery/types/Message.tsx
@@ -8,7 +8,6 @@ import * as MIME from '../../../../types/MIME';
 import { arrayBufferToObjectURL } from '../../../../util/arrayBufferToObjectURL';
 import { Attachment } from '../../../../types/Attachment';
 import { MapAsync } from '../../../../types/MapAsync';
-import { MIMEType } from '../../../../types/MIME';
 
 export type Message = {
   id: string;
@@ -16,8 +15,6 @@ export type Message = {
   received_at: number;
 } & { objectURL?: string };
 
-const DEFAULT_CONTENT_TYPE: MIMEType = 'application/octet-stream' as MIMEType;
-
 export const loadWithObjectURL = (loadMessage: MapAsync<Message>) => async (
   messages: Array<Message>
 ): Promise<Array<Message>> => {
@@ -51,17 +48,17 @@ const hasVideoAttachment = (message: Message): boolean =>
       MIME.isVideo(attachment.contentType)
   );
 
-const withObjectURL = (message: Message): Message => {
+export const withObjectURL = (message: Message): Message => {
   if (message.attachments.length === 0) {
     throw new TypeError('`message.attachments` cannot be empty');
   }
 
   const attachment = message.attachments[0];
-  if (typeof attachment.contentType === 'undefined') {
+  if (is.undefined(attachment.contentType)) {
     throw new TypeError('`attachment.contentType` is required');
   }
 
-  if (MIME.isVideo(attachment.contentType)) {
+  if (is.undefined(attachment.data) && MIME.isVideo(attachment.contentType)) {
     return {
       ...message,
       objectURL: 'images/video.svg',
@@ -70,7 +67,7 @@ const withObjectURL = (message: Message): Message => {
 
   const objectURL = arrayBufferToObjectURL({
     data: attachment.data,
-    type: attachment.contentType || DEFAULT_CONTENT_TYPE,
+    type: attachment.contentType,
   });
   return {
     ...message,