is a large triptych painting by Hieronymous Bosch. It is, believe it or not, a religious work. The small image is a small piece of the right wing of the triptych.
It's one of the most truly weird paintings of all time, in my opinion, and there's even been a pulp-scifi book written around it (Wild Cards XI, "Dealer's Choice", G.R.R. Martin, ed).
The WebMuseum has a display of the entire painting.