Uploaded animated WEBP files do not post for download

[tostanoski]

Description:

When uploading an animated WEBP file, it appears to upload successfully, but doesn't become available in the channel it was uploaded to. No post occurs following the upload. Still WEBP images work properly; only animated variants are broken.

Server Setup Information:

• Version of Rocket.Chat Server: 0.63.3
• Operating System: Mac OS 10.13.4/Windows 10
• Deployment Method(snap/docker/tar/etc): All
• Number of Running Instances: 1
• DB Replicaset Oplog:
• Node Version:
• mongoDB Version:

Steps to Reproduce:

1. Attempt to upload an animated WEBP file. As these are uncommon still, here's an example.
2. Watch it upload as any standard file.
3. View results.

Expected behavior:

The file should be visible in the channel to download. In the apps, and in supported browsers (Chrome and Opera currently, as this is a proprietary Google format), the image should render.

Actual behavior:

No post appears and the file is not available in the channel view.

Relevant logs:

[FredericaBernkastel]

Still up, version 2.1.0