Is there a way to make a piece of art look larger when the frame is kinda dull and simple?

I've seen people paint the wall behind the painting a contrast color in the same shape as the framed painting (leaving the rest of the wall the original color). Then frame the contrast color area with stained molding. It's an interesting way to highlight a piece of art.

You could also highlight it with a pot light.

Or you could reframe it