Aphantasia is about the mind's eye, not visual memory. Many people with aphantasia can still remember visual/spatial details of memories, they just can't see them. Not sure if those had to be recorded at the time of the memory or if they can be derived later, though. Based on some cursory research, it's not particularly uncommon for aphantasics to build a habit of intentionally making spatial observations in the moment for potential recall later.
If you take something like the “draw a bike” test, I have to wonder if the “normal” folks have any visual memory.
It’s always been curious to me that there’s this idea that people can “see” anything they wish, but then do not know what common objects look like. Whereas I’d wager any aphantastic would nail that particular test.