If you bothered to take the time to learn the science behind camera lenses, you might find out that lens glass is spherical, therefore, it distorts the subject by default. Depending on the length of the lens, rarely, and I do mean rarely, does any photo tell the precise truth about the cock in a photo.
The only way to "accept the dick that the guy has," you have to hire the guy and see the cock in person.
In most cases, a photo of a cock is pure fantasy because of the science of photography. This might explain why Al Parker was famous for telling his fans "blame my cock size on the cameraman." And that's before Photoshop. Lighting and camera angles make a difference, too. It's the same reason why a lot of people don't look like their photos when met in person. Or, a pro model looks ordinary in person but looks extraordinary in photos. Either the science works or it doesn't.
Many would argue, and I would agree, that Photoshop in porn is necessary to get closer to the truth. The chances of getting the cock, the face, and the body muscles all in the right place at the right time is VERY challenging and time consuming. In a porn photo shoot, 9 times out of 10 the face and the body will be perfectly composed, but the cock will have drooped. In digital, it is very easy to replace the droopy dick with the one that's full-mast from another frame. Why settle for half-mast if you don't have to?
For the sake of believability, the key is to hire someone who knows what he is doing.
On top of all this, entertainment is the point, especially if I have to entertain myself.