When you compare a mirror vs camera, it's not like either one is automatically the way other people see you. As Visuals Clipping puts it, a mirror shows you in reverse and a camera doesn't have that same effect. And then there's the way a camera lens can make your proportions look a bit off depending on how far away it is from you. And let's not forget familiarity - we're all used to seeing ourselves in the mirror, but photos of ourselves can look really different.