I don't believe the idea that images of 'suspects' appearing on the internet was a good or bad thing. Inevitably, the images were going to appear as they were broadcast and made available. However, the idea of vigilante justice, I believe, was a bad thing. The result I am talking about specifically refers to Reddit and the idea that internet sleuths can solve a crime based on images alone. This side of the internet resulted in cases of mis-identity with very real consequences from anonymous sources, tips, biases, etc.
Yet, the good side of mass media was the amount of evidence provided in order to identify those who were involved. The "justice" should not have been crowd-sourced, but rather the process of gathering evidence. The amount of video, photographs, and other forms of information that authorities were able to gather on such short notice was amazing. It is re-assuring, but also a bit scary, when one is confronted with how much information is available.