"hey bro" is the act of taking a picture of a girls ass/boobs.
"hey bro" is used because girls don't understand it when it is used, so it can be used even when in the vicinity of the girl whose ass/boobs you want to take a picture of.
the album in which you keep the pictures of ass/boobs you have taken.
dude, i used my camera phone to "hey bro" that girl
I just added sally to the "hey bro" folder on my computer