They are seperated in multiple pngs. There are more than 3000 fakemon family lines and all lines have 3 stages. Each fakemon stage consist contains 3 unique sprites, front, back and icon.
I'm not a lawyer and this is not legal advice but, as long as you're not making a one-to-one copy and are creating a unique game you should be fine. This is common for many successful monster catcher and fakemon games out there.
