Find two very different images that you wouldn't normally imagine together, such as done with the movie Cowboys and Alien.
Once you have the two ideas, imagine them together. For example, alligators and song birds don't at first seem to belong in the same closed space, but they certainly bring to mind a quick image, perhaps one with the alligators eating songbirds, their feathers strewn about in the mayhem of the gory scene. On the other hand, it could be paradise if these two could reside in close company. Maybe you would prefer unicorns and moles. At first I thought of moles as little furry animals underground, but what if they were actual moles on the skin that would erupt and destroy the pristine white coat of the unicorn, a symptom of a serious disease.
Use whatever images you bring together to inspire you to create a scene or event.