There are people interested in overcoming aphantasia (or hypophantasia, an extremely weak form of imagination).

Today I have medium-ish hypophantasia, but I remember when I was doing phantasia exercises, in particular "snapshotting" and "memory streaming", at least two times, there was a subtle shift in my perception and all of a sudden I could remember a ton of things, as if I opened a door. It would only last maybe 10-20 minutes (I would practice 30 - 60 minutes per day).

It wouldn't surprise me a bunch of those memories are in the brain but you just don't have access to them in everyday waking consciousness.

So, for me, it feels like a lot of my memories are visually indexed, and if I can't visualize then I can't remember, but once I configure my mind through meditation and these exercises, it is like I can "tune my mind" to mind's eye access (radio/TV analogy here) and with it the memories.

Then once I stopped the exercise (for the day) it would go away in around 10-20 minutes (kind of like how a muscle pump goes away rather quickly after exercising).