For example, in the episode with the time machine. When Squidward goes back in time and finds Spongebob and Patrick all caveman-like, they show their teeth and it goes to a painting of Patrick's teeth, all detailed and everything.
This happens in most episodes, I think, in various situations. I'm just trying to figure out, who the heck paints these (it seems like they are all done by the same person) and where can I download a collection of them, or even buy a nice print of one?