I think the requirement should be only a single photo
I agree completely. Making it as simple as possible, but also making it obvious that the Waymark was visited is best.
Kind of coincidentally, I had a recent Visit on my Half Dome Waymark (in the Summits Category), where the individual merely posted, "Cool! I didn't know you could see this from The Valley". I'm sorry, but standing on the Valley floor is not quite the same as making the 16 mile round trip, 5,000 vertical hike to the summit.