It apparently doesn’t have to be as realistic as hallucinating or dreaming to be exceptional though. There are tests for aphantasia that involve picturing a loved one, their face, then some common piece of clothing they wear and if you can see them clearly in your mind and describe them as if they were in front of you that is something reasonably out of the ordinary. You might be “hyperphantasic” too

https://aphantasia.com/study/vviq