I was just thinking of a couple categories that would benefit from having the picture requirement removed.
The types would be things that aren't 'inventoried' in google, and one doesn't look that much different from another.
My examples would be Tennis Courts and Basketball courts. They are both worthy categories. If you want to find a Tennis Court, an accurate inventory on Waymarking.com would be very valuable to have. It's not available anywhere else (that I know of). I just cannot excite myself over taking and uploading pictures of them (very often). If they removed the photo requirement, I would pop coords and upload the park name and location much more often. In the end the category would be more valuable without a photo requirement. There could even be a default graphic to fill in the hole and make the page prettier if there wasn't a photo.