I think the point is that TM's picture is not a flattering picture. The media chose to present flattering photos of TM and an unflattering photo of GZ. IMO, they are both attractive men in their "good" shots. Not so much in the others. And people often perceive good looking people as "good."
Sad to say, when I saw GZ's mugshot, my first thought was "what a." He looks menacing in that pic, completely opposite in this newer one.
(Hope I've made sense.)
It shows attitude, IMHO. It's not like an accidental unflattering shot with eyes closed or mouth open - he posed that way, and liked the photo enough to publish it. Trayvon didn't think it was "unflattering", but older people do.