as much as I hate to agree with ARSEN (
) there could be circumstances in which a gun is fired at close range and the amount of blood transferred to the shooter is too little to easily see in those camera shots we got from the police station. I don't think such circumstances are common, but they are possible. It is very likely that if you actually were to analyze the clothing Zimmerman was wearing you could easily tell he discharged his weapon, but be unable to tell from the overhead view we had.
More interesting than that to me is that the footage does tend to show that Zimmerman's injuries did not appear so severe as to need any sort of immediate care, but we already knew this... if they did, he wouldn't have gone home for the night after he went to the station, he would have sought medical attention