I have heard it called a “visual metaphor”.
My favorite example is a scene from Easy Rider. In the foreground, Peter Fonda is changing the tire on his motorcycle. In the background, a cowboy is shoeing his horse.
The one that comes to mind is, I think, from Mel Brooks’ Silent Movie (or maybe Young Frankenstein). The character has a brilliant idea and a standard light behind him comes on at that instant, so you get the lightbulb-moment thing quite literally. I guess I’d call it superimposition.