There are reputable agencies and there are reputable independents. Doing your research here will help you know which ones are. There are reviews of agencies here on TER as well as all the provider reviews. For the agency reviews click on "Site Reviews" at the top of the page then go from there on the menu choices. I use an agency a lot. I see independents too. I like the agency because I'm screened there. It's a one time thing and now whenever I want to see someone especially if they are new, I call, set the day and time, and I'm in. No back and forth required. The agencies I use have a 60/40 split with the providers. The provider gets 60 % of the donation the agency gets 40%. I can't speak for the photos you mentioned but the photos of the providers I see and have seen at the agencies I use are right on.
Bottom line whether agency or independent do your homework. Check them out here and by back channel with reviewers to see what their reputation is.
To be able to do that in the best manner possible you need VIP membership here so you can see all the details of the reviews and can use the PM system to back channel with other reviewers.