Oh, sorry, there was no ongoing testing; I just asked everyone to set up Gravatars… Now I can’t reproduce the problem because I can’t figure out how to get it to load the Twitter avatar in the first place. It either displays the local one or falls back on Gravatar, which seems reasonable.
This may be unrelated, but there must’ve been an input field #twitter_id in the dialog on the profile page, but I don’t see it anymore.
