There’s definitely memorization, but there’s just a ton of tricks that aren’t explicitly memorizing the images themselves.

They can sometimes narrow down the area based on the car that’s taking the images, or how wide the lens is. Things like that. If they see a red toyota corolla is the car taking the photos- which they can tell based on the mirrors appearing- they know it’s specifically mainland malaysia.

Very small context based clues a lot of the time.