I agree with coriander1992. I believe everyone here who posts their pics has it to some degree or another,otherwise why would they bother posting here? And hows does tattoos exempt someone from having SA? I imagine tatttoos is alot of peoples way of trying to deal with it. If you get tattoos you can walk into places inviting disapproval, but that disapproval will be for the tattoos on your arms and not you personally. I think it is a good way of coping and distracting attention from you. If someone doesn't like you you could easily believe it's because of the tatttoos and nothing you did in that situation, which might be comforting..
For me if I am with a friend someone the SA doesn't really affect me, but it affects me to a frightening degree in school environments, I can't even speak. So I could post pics of myself at home with a friend and I'm sure I would look mentally healthy, but if you were to see a pic of me in school I would look ready to k i l l m y s e l f. lol
As AquariusOutkast said, SA doesn't pick you based on how you look. Anyone can have it. It is caused by many things. It can be genetic, which it might be in my case since my mother has it, and my twin brother has it, but not my other two siblings; it can be inherent through observing a parents behavior or someone else, it can be learned that way. Both of those causes have nothing to do with appearance. It can also be caused through traumatic negative experiences, and surely people who stand out as odd might be bullied more in school so odd looking people might pick it up more that way. I was harassed and bullied merciliessly for over 7 years of my life, so I think that contributed to mine as well. I think mine was caused by a number of these factors.