I don't think there's a way to be completely sure though. The game is programmed by trying to fetch an image corresponding to the player's coordinate position, and it's just blank white if no image is found. The game has horizontal boundaries but not vertical; you can just keep jumping up forever. Most of it will just be whitespace. The people who auto-generated maps would have found a lot of empty space and decided to call it quits after some reasonable time, but there's still a small chance that Randall would have hidden some image way high up past what anybody would reasonably search.
On an unrelated note,
