I was kind of leery of making this global because I didn’t want it to affect thumbnails on the thread index, since they must be confined to a finite area, whereas in a thread they can flex downward. (The fetched image can be an arbitary size.) But it looks like they don’t use the same selector, so should be safe.

Edit: I’ve updated it to support thread index, inline images, and profile pages and the differing aspect ratios