My memory is failing me at the moment. Was Tsarnaev already tried and found guilty? Did he confess? I am not saying that he is innocent, but neither do I think the other set of pictures were appropriate either.
He has plead not guilty to the charges. I think the cop did a brave thing. He knew he would most likely be let go, but released a different image of the suspect than what the public is used to. Maybe the teenagers on the internet who think he's "hot" will have second thoughts.