Make a game or something for a game, inspired by paintings.

Make dungeons and hex crawls inspired by medieval art or by picasso.

Make an rpg where the key mechanic is poorly painted renaissance jesuses or  a game telling the story of a grecian vase. Make a bestiary inspired by the Book of Mountains and Seas.

Charge as much as you want for it, go wild. 

(additional rules; don't be a racist, fascist, queerphobic or boring.  whatever art you're inspired about, respect the context that it came from and the culture that produced it. Please use content notes as appropriate especially if there's anything in the paintings that is nsfw. if you are using art that's been produced recently, particularly by smaller artists and creators, MAKE SURE you credit the artists involved and ask them if its ok!)