I don't know if it's been reported yet, looking briefly through topics I didn't see anything on it, but if a player has uploaded an icon that is too short, vertically, that player can't be promoted to GM. I wasn't planning to, but at least had to option to for the other players in the campaign. Hovering over their icon, I see the option to promote them, but if I try to go do so, as soon as I get to the bottom of their icon, the option goes away.
I'm running Firefox, latest version for Windows 7, and running 7 as my OS.