I cropped this picture of Trayvon Martin from what MSNBC released to incite violence. It is immediately apparent that this picture has been doctored. We know from the trial that he had grass stains on his knees. If you have Photoshop, you can also zoom in on the top of his right hand: the color is different and his knuckles are removed.
This is another poor attempt to manipulate the news instead of reporting it.
Original picture at the Gawker.