As you can see above, Ben doesn't have a profile picture. This is expected for me, as his picture is being blocked by Ghostery for me. I have gravatar whitelisted but not other sites, and his happens to be pulled from another site.
The space where his image would be, however, is not properly allocated. It is replaced by the alt text, which, for a short username is ok (not the proper spacing, which is bothersome for layout of the rest of the row, but doesn't look that ugly (but a little)) but for a long name, it can take up quite a bit of space.
It'd be great if the width for avatars was specified by the styling so that my chat pane didn't look funky when a user with a blocked photo join the discussion.
On Firefox 32, though I would imagine this isn't limited to one browser.