I do actually make them myself. I'm not exactly an artist, but I bought myself a cheap graphics tablet a while back, so figured I'd do a first pass on the art. This is also why the characters have no faces, because I'm not good enough an artist to draw faces, so chose to go for a simpler design.
Cover screen is the only art I didn't do. The throne with the crown is done by an actual professional artist, by the name of Derek Restivo.