From what I can tell looking at those pics, in conjunction with the difference in pec development your right shoulder is higher and more protracted (pulled forward) than the left side, while your right anterior deltoid is more developed than your left.
This would lead me to assume that you are compensating for lack of strength on the right pec with your ant delt. As a result of, and perhaps due to your form and exercise selection causing muscular imbalances, you've created a postural deviation and an imbalance in muscular development.
Br