But this is images. I submitted it one time and I'm pretty sure that was hundreds of images. You basically walk around the POI and it takes a LOT of images of the POI. 600 scans / player would be insane.

30B images over the course of 6 years by a few million players. In a game that runs daily quests like this and weekly quests can easily be accounted for by a small fraction of users. I don't know how much you played Pokemon Go, but when the AR scanning tasks were introduced, most players didn't really want to do them, which resulted in the tasks be segregated from Field Research (since they were taking up a valuable spot)

This was GP's original point - it doesn't take the majority of people playing Pokemon Go to do it in order for them to get 30B images, especially since each scan was like multiple images - you look like a dork doing the scan