If you see a bus crash into someone’s front porch while a caged dog barks in the side yard, near a man in a business suit who is grilling hamburgers, you might call that a surreal image. Things that are surreal combine unrelated elements to create a bizarre scene.
The adjective surreal comes from Surrealism, a movement that produced films, writing, painting, and other art forms that often contained irrational, disjointed images. So, surreal describes something that’s a bizarre mix of elements, often jarring and seemingly nonsensical. Images can be surreal, like the melting clocks in Salvador Dali's paintings, but so can strange, dream-like moments in everyday life.