A photo taken of oneself in his or her bathroom mirror usually with a cellular telephone camera. Mirror shots are taken by either toolbags or sluts that usually post them to social sites in order to gain attention either through compliments (eg "bra, you're so ripped!") or criticisms (eg bra, you're so gay). The duchiest of mirror shots are those that are taken without a shirt on, usually accompanied by sunglasses and/or by a face known as a "grill". Females taking mirror shots usually expose large amounts of cleavage and often push out their rear ends to appear like they have more "junk in the trunk" then in actuality. People who post these mirror shots are likely candidates for mirror masterbation although that is not always the case.
Bra did you see John's mirror shot he just posted? He's so gay.