To add onto that, on the Jerboa app (not sure about other apps), if I try to click on an image in a comment, it just minimizes the comment. I'd love to be able to click on pictures in comments, as well, and have the thumbnail expand.
Connect does this too. It's dumb. There's not even a contextual long press option to open externally or anything. I'm sure it'll come eventually, but it sucks as it is right now.