It needs some kind of outline around the dragon and writing, otherwise it might not be as easy to see and read.
Maybe an outline that fits in with each skin or something? I don't know about the different skins - either you can have different buttons on each skin, or there's an option somewhere else for buttons that are the same no matter what skin you use.
Which is why I said a black background would be preferable over a transparent one. That way, no matter what skin you use at Zelaron, you see the same clarity in the dragon.