I'm sure it's size is the same, but when I make a cuckold take a picture of me fucking his wife my cock feels thicker and longer. It energizes me as a sexual being and makes me want to take her even harder.
Depending on the wife, the reaction can vary. Most love it when I have their hubbies do my bidding and boss them around. Others like the exhibitionist factor of being photographed. None of them ever complain.