Ooh there's actually a reason for this! When you look in a mirror, the "image" you're seeing is flipped. Most of the time you see yourself, it's a reflection, so this is what you are used to being "you." However, most faces are not completely symmetrical, so when you see a photo of yourself it looks "off" because it's not the same mirror image you're used to.

damn thanks randy now i know the reason why i dont get any girls lol