I don't know...for mine it says this "Note: The maximum size of your custom image is 100 by 100 pixels or 64.0 KB (whichever is smaller)."
but that's if only i browse through my device. I don't get this thing....Also, there's a blue dot that says this too "Do not use an avatar" whenever i try to edit my avatar...i don't what's up with these stuff.
Sorry for confusing u if you don't know any of this stuff!!