This feature request is still being reviewed by the feature team.
As John Melendy has stated, we need the ability to hide/block/disable gifs for a particular channel and/or user.
Since gifs affect each user differently (some love them, others hate them), this should not solely be in the control of the admin of the teams application within the office, or the admin of a channel, but up to each user to turn on/off these possibly unwanted features, since they will not affect the usefulness of teams if they are disabled.
Personally my co-worker spams me with occasional gifs and it's annoying. Blocking him seems a bit too far since he's usually useful. The ability to disable gifs will at least put that feature back in my control; where it belonged to begin with.
E.g., Facebook allows you to hide or block certain types of posts/images without un-liking or unfriending a page/user entirely.