It doesn't have to be a screen even, it can be anything. I have noticed that I will have an almost exact replica "burned into" my vision when I close my eyes. I can then (somewhat) manipulate this image in my mind. I've kinda thought that these changes in light (from whatever we are looking at) creates the initial image and then this image can be manipulated in the mind. I think that the retina or the parts of the brain that are involved in visual imagery must somehow be involved in these visualizations we are seeing (not the after image). It would be inefficient to develop a new skill from scratch, a big part of our brain is already dedicated to sight and imagery, so I wonder if we can somehow make use of the visual cortex to enhance our ability to visualize things?
Need to find a way to hack into the subconscious..