Copyright question (Patreon)

Do any of my subscribers have a law degree? According to what I've read, the person who painted Rick broke copyright law. So is it unlawful if I were to sell images that contain part of his/her not-so-original work?

(A reminder that my Patreon profile makes explicit that I'm not selling access to these images, by featuring them on Patreon. My question is about other creative endeavors with the images.)