What still is a UI-problem in the Mastodon webinterface is:
Try to open a thread without clicking on reply or copying the toots-URL into the search, when the toots only content is an image.
You just can't there's no space to get the mouse into, not even a pixel.
There should be some space around the picture or at least above it.
If there's text, it just works fine.
Reproduce: Upload an image without any text in the content or any warning text.