Can people really “see” images that they picture in their head?

I got in a debate with my girlfriend about this. When I asked her to visualize her dog, she told me it is just like seeing a movie of her dog in her head.

When I picture a dog, I kind of have a general idea about what dogs look like and their physical traits, but definitely not like seeing with my eyes or watching a movie.

This sounds like a dumb question, but what’s it like for you?