From the FAQ:
- I can’t draw/pixel/compose/etc. Can I use someone else’s work or asset packs? Are contestants allowed to use already made assets?
Yes, but only if you have the rights to it. It depends on the copyright attached to the resource you have in question. Make sure you are 100% sure a resource is free for use, or is under a Creative Commons License. If you’re not sure, it’s always safe to ask the content creator! However, your best bet is to use resources in the public domain.