This is a photo from the live stream of the Occupy Protest in New York. The person in the purple sweater was shown being arrested by dozens of police officers and another protestor snapped a photo of the bloodied man after supposedly being hit by a police baton.

[Update 12:16pm MST]

From reports by a live streamer, the man was kicking barricades around the park and the police were required to chase him to get him to stop in which he fell over and bumped his head which caused the injury. The police then continued to talk to him and were required to control him while they did so.