My theory is that guys in porn look so big due to the effect known as, "the camera adds 15 pounds." I believe this can be extended to penis size, particularly girth. So don't feel bad if you don't hang like a pornstar - I bet they don't either.
Never fear, this thread does have a purpose -
How do your partners' interpretations of your size differ from your own? Are you surprised at your size when you take pics? Do you expect it to be bigger, smaller, the same? How good are your partners at estimating your size? None of mine have been very accurate.