I expect that we will see them eventually, after the decision is made to prosecute or not. If a decision is made to prosecute, then it might not be until after a trial.
George Zimmerman is under a legal impediment in this trial by public opinion. He is almost certainly under orders not to say anything, and the police are not releasing evidence while the investigation is underway.
The injuries were reported quite early. At least some reports said that he required stitches to the wounds in the back of the head.
But, this does not fit the frenzy the media and the race/grievance activists are feeding and want, so that information is pretty much being ignored.
Plus they keep posting a picture of the kid when he was ten years old.