whether the girl takes the picture herself, or not and whether it was done on purpose or not is usually unknown.
some funny things to note about these are; if she has one, she usually has a bunch more.... and also, if word gets around about you and or someone else relieving themselves to these photos, the girl usually winds up getting all pissed and offended. if you don't want guys getting stiff/girls getting wet to your whore-ish cleavage shots, then DON'T FUCKING POST THEM!!!!
Girl2: "CLEAVAGE SHOT!!!!"
Girl1: "Ow! My boobs!"