It turns out posting animated GIFs on flickr is way convoluted. 1) You have to be a pro user, 2) You have to post a GIF, flickr flattens it, then you post a comment with an image link to the original GIF you just posted. (The original sized image isn’t flattened). Because of the flickr pro requirement it doesn’t really seem worthwhile at this point. But if a ton of people request it I’ll give it a shot!