The woman in the mirror

When I look in the mirror I see a chubby girl with a cute face. I see plenty of flaws but in general I like myself. Yes I know I'm bigger than I need to be and I could work on a lot of things, but I like who I am. Then someone will take a picture of me and it's nothing like what I see when I look in the mirror. Why is that? I look 10 times bigger, everything  just looks worse. I don't understand it. Am I seeing things or is it that bad really?