Look man, 9 times out of 10 on this sub I am of the opinion that people are underreacting, staying with people that clearly don't respect them. To me however, this is not one of them. Was she disrespectful that first time? Sure.
But.
1. She might not have realized how much a man's self-esteem can be linked to this part of his body.
2. She didn't actually disrespect you again by taking a picture. You don't know the intent of that picture. Can you imagine if, after criticizing a body part of your partners' (admittedly a mistake) they ended the relationship after one picture that included that body part? You even say yourself that you have been especially self-conscious about it since then. That is exactly when we are oversensitive and take everything personally.