First, yes, it's crap money for work!
But I feel for the national and state parks. Their budgets are cut constantly, their staff is cut, and their services suffer. Then we **** cuz they're shutting down parks or limiting access.
So I'd do something like this to help the park. Not to make money, but to help the park.
A lot of parks have gone to online reservation services (like Reserve America). Sounds like they want to offer a picture of each site because, as a camper, I want to know if there's shade, room for a slide out, how close we are to the next site, etc. I can see having a picture of the actual campsite, kind of a nice idea.
So if you move past doing it for money and maybe take the time/effort as volunteer effort, you'll do better. You could even forego the fee and bill it as a charitable deduction at $250/image!