A person who's head is cropped significantly smaller or larger than the rest of the people surrounding them in a yearbook or composite photo.
Homey: "Dude, look at Adrian's head in this composite photo. That thing looks like the goddamn Goodyear Blimp."
Buddy: "Yeah, he's a total photard. I think the cameraman got the framing wrong during photo day, but there are also rumors that he inhaled several massive hits of helium just before that shot was taken."