There are reasons for that:
A) A perp walk picture allows potential jurors to see the suspect before he's cleaned up by his lawyer and given a pair of glasses to wear in court.
B)Seeing pictures of the suspect might prompt other victims to come forward and identify him.
Oh I understand why a few pictures make sense. You make good points. I was talking about pictures that appear long after the investigation is over. We had some people on trial for a horrible crime near South Bend, IN, and it seemed like the local paper put up a picture of the perps every day for weeks or months throughout the trial. It was the dead victims who deserve to be seen and remembered -- not the killer.