The instability and detail-injection has been a fairly big question-mark for me as well. I can completely believe people "see" things at will, and many I've ru

The instability and detail-injection has been a fairly big question-mark for me as well. I can completely believe people "see" things at will, and many I've run across claim it's "as real as real-life", but then they immediately fail to answer any simple questions about it. Like if the seat on their visualized bicycle is in front of or behind the rear wheel. Even ignoring if their answer makes physical sense, most of the time there's a significant pause while they try to decide, and something like half of the time they change their mind later. I suspect it's more like dreaming of a thing than a photograph-like construct, at least in a significant number of cases. It'd also explain why it seems so dream-like when you get into specifics, where the pieces may make sense but they do not even remotely add up to a coherent whole - context or something is lost each time it's visualized. The main important part is that it feels like seeing a thing, which is both 1) something not everyone can do/achieve, and 2) more than sufficient for individual use or broad concepts. And it can probably be trained to be more stable and detailed, and there are rare outliers where it's significantly better - there do seem to be people capable of maintaining a stable "thing" from inception through real-world construction.