I do not allow anyone to use my art or covers in any of their works without express permission from me, and I plan to keep it this way for now. I have had past instances of people reusing my content without giving me credit or even giving me knowledge about it in the first place, so I have become a bit paranoid of that happening again. I wish to minimize content theft as much as possible even if my art may not seem worthy of being stolen.

I'm sorry, but that's just how it is.