You are correct that there are no photos in his gallery but I don't think that means he didn't upload any photos. Here is his
visit log for the Georgia Historical Marker mentioned by Chapterhouse. There is indeed a photo there for that visit.
The gallery is only for waymarks owned by a user and not for visited waymarks as far as I can tell.
The Filter indicates it is for images uploaded to a users collection of waymarks not for images of waymark visits.
This is born out when I check my gallery. Only the photos I posted to a waymark I own show up and interestingly enough it shows others images as well if they visited my waymark listing. The gallery on my profile page appears to be for all photos that are uploaded to my waymarks.
All that said, it is clear the user is an armchair waymarker by the nature of the visits. I have deleted his visits from the categories where I can. I
This has been a beneficial thread to me. I have learned how to filter a bit in the gallery but still do not know why my gallery would not work for a time this morning.