Okay, I've seen a report that avatars are still buggy when first uploaded.

If you upload an avatar and on the EDIT page it shows correctly - it's on the server and working. The problem arises when you go back to view your profile it might still show the question mark.

Near as I can figure, your browser has cached the question mark image and is showing it in place of the new one. Refresh the page and your avatar should appear. If not try clearing your browser cache and refresh the page again and see if it updates.

If anyone having this problem can report back here, that would be great!
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This is my sig. You wish your sig was this cool.