You usually need photos of every pump (there are exceptions, depending on the brand), in addition to various other elements of the gas station, including the canopy, convenience store exterior, store counter, overall location, etc. I find it useful to take photos of every single thing I see and then pick the ones to upload later. You might get your report sent back to you for some kind of quality control issue until you get the hang of the audits. However, they are some of my favorite shops to do, and I love seeing the Maritz deposits in my bank account!
I might also add that Maritz is very responsive by phone. Although they are strict and occasionally unswayed by explanations of different circumstances, the opportunity to talk to a real person means a lot to me.