Imagery and hallucination look related but aren't the same thing. This covers pseudo-hallucinations, the Ganzflicker effect, and where perception and imagination overlap.

This apple illusion allows people who can't visualize to temporarily 'see' an image that isn't there—using visual perception to demonstrate what others experience through their imagination.
Aphantasia Network · October 2023

On rare occasions in the morning, between sleep and awake, when the images from my dreams float behind my eyes, that’s when I revel in what it must be like to “see” imagery.
Liana Scott · December 2022