The save settings are incorrect. If you're using Paint.net, you can choose the compression type. For icons, you need A8R8G8B8; there's also a similar type that starts with X instead of A – do NOT choose that one.
Now, there are only two questions left:
1) Is it possible to change the spells of the whip attack?
2) Is it possible to make the acid breath effect apply to two creatures at once?
