Board Thread:General Discussion/@comment-26316686-20150501115613/@comment-303594-20150501123317

Look at Wikia, brain the size of a planet and it doesn't even support PNG avatars.

Your avatar is actually served as a JPG - even though it's stored as a PNG. This is why you don't see the alpha.

I'm not sure if Wikia's ever said why, but I don't think they're likely to change this any time soon. You're welcome to contact them at Special:Contact/general to put forward that you'd like this change though.