Filter options for different media types

[eishiya]

Pitch

It would be nice to be able to set particular filters to only apply if the post has a particular media type, similar to how we can already apply filters in specific contexts. The options could be No Media/Polls/Images/GIFs/Video/Audio, or whatever media types Mastodon is able to discern.

In addition to narrowing where keyword filters apply, this should also be usable to hide any post with certain media types, i.e. it should be possible to create a working filter with no keywords as long as at least one content type filter is set.

Motivation

Filters are already a good way to curate one's own Mastodon experience, and I think filtering by media type would take this even further. In my own experience, two types of things often make me wish this were an option:

• As a general rule, I do not watch videos on Mastodon, and I would prefer not to see video posts at all. They stretch the timeline (especially now that the 16:9 thumbnail option is gone) and they startle me when I occasionally click the thumbnail expecting an image, which isn't great for my health. In the rare scenario where I'm feeling up to watching a video, I'd be able to click "show anyway" on the post and potentially view it.
• There are some tags and topics I don't mind reading about, but which I dislike seeing in media. For example, I might want to block AI-related posts with media because I don't want to see AI-generated imagery, but I don't mind seeing text posts on the subject. On the other hand, there are some tags that I want to filter out when they're text posts but don't mind seeing with media, such as certain discourse-prone video games I don't mind seeing art and screenshots of.

Some users may prefer to filter posts with media types that they can only experience via alt text, as well.

In my list of media above, I included GIFs as distinct from Video, as it seems that Mastodon distinguishes the two, and labels any silent video a "GIF". I think this is a useful distinction for filtering, as some people's might not want anything with audio (so they might filter video and audio but not GIFs), while others don't want to see anything animated (so they might filter GIFs and video, but not audio).