I think there is a confusion that visualisation must be photo-realistic. I can visualise the entire city in which I live in my head, and fly around its streets, parks, and landmarks in a handful of seconds. The map is fully accurate and the broad-brush image is. But if I stop and focus on any one detail, I cannot always remember exactly what lies there. Clearly my memory depends on filling this in 'as-if' to sustain my vision, and I think this is true in general. We don't have memories that can zoom in to ever greater microscopic detail, and we don't have every detail of a picture, but this doesn't stop us from imagining.

It's similar to the way in which when we're presented with words that are jumbled up apart from their first and last letter, our brain fills in what's happening. Vision in general is not just the mechanical encoding of sense data from light. It is as much psychological as physiological. We see the world in stable colours and contrasts because our mind controls for illumination and processes the colour of one detail relative to the whole picture. I think our mind's eye depends on similar kinds of psychological support.

Isn’t it more likely that memory isn’t perfect? I can picture a bike in my head. I can rotate it, crush it with a giant boulder, splash it with paint etc. Those are very visual things in my head. But do I remember the exact configuration of spokes on my own bike? Not really.

When you dream, do you "see" things? Ever tried doing math or remembering a password or phone number in a dream? It's similar to that. A blurry picture is a pretty good analogy, except it seems sharp. If you look at the bottom of the bike you see gears, pedals, chains, but it's hard to see how they connect. It's a patchwork of concepts.

Since we're talking internal experience here, I have no idea what your distinction is between visualization and a delusion of visualization. Fwiw, even though I don't think you'll really believe me given your other comments, visualization of actual real life stuff for me is similar seeing stuff in the corner of your eye where you're brain kind of automatically fills things in but in a way that isn't very legible. As long as you don't have tunnel vision, surely you can relate to having seen something without knowing the details?

My actual complaint runs deeper though. My experience of visualizing can't be a delusion because I'm describing my internal experience. You can claim I'm lying about my experience, but what you can't do is claim I'm actually experiencing something else and not noticing. If I didn't notice, then no, I did not experience that other thing.

That's those specific people. I can draw a correct image of a bicycle from memory. It won't look exactly like my visualization because I'm only average at the physical act of drawing, but there won't be anything technically wrong with it.

A bicycle shop owner would surely draw it perfectly from memory because he's familiar with their workings. People who have used them occasionally for transportation are aware of the general appearance of a bicycle, but will have trouble visualizing the details unless they've actually paid attention to them, and start guessing, just like it happens in dreams. they won't have trouble imagining the parts they're familiar with, like wheels, pedals and handlebars.

Also, I can imagine my wife's face almost perfectly, but any attempt to draw her will result in a monstrosity because I suck at drawing.