That's kind of what I've been trying to figure out: when people say they count sheep, do they close their eyes and literally see sheep jumping over a fence as if watching a movie or wearing a VR headset? Even in low resolution... That would be pretty impressive... why would we still need movies and games then? ;)

Of course I can imagine sheep jumping over a fence, even in vivid detail, but this imagining is not really seeing visually like in real life, not even like in a dream. As I said, I would describe seeing things that aren't there (with closed eyelids or not) as hallucinating. Perhaps not being able to do that at will is aphantasia, I don't know, but it would blow my mind if it were