Feature Request: Add ability to collapse visual media

[chpatton013]

Please add the ability to collapse visual media in all applications.

Visual media is much easier for wandering eyes to consume than snippets of text. There is currently no way to temporarily hide media when in public settings. Instead, you must "Delete for me", and then the media is permanently lost to you.

The bare-minimum implementation of this feature involves a collapse/expand option next to each media message. A full-feature implementation adds controls to collapse-/expand-all media in a chat or group, and a persistent user (and/or device) setting to collapse or expand media by default.

I'm pulling inspiration for this feature request both from Slack and the Reddit Enhancement Suite chrome extension, though I'm sure there are other great examples of this feature in other applications.