I know people that are not very pretty in person but look really good in pictures and vice versa. Its all about being photogenic or not. I don't like how I look in pictures but I feel pretty when I look in the mirror. Very few people or photogenic so I wouldn't let a picture define how you think of yourself.
yh its the same for me... usually has to do with lighting or flash or w/e . but your as beautiful as you think you are.. your confidence will seal the deal. If you are comfortable with yourself people will be comfortable with you :)