Here is an interesting, though not really new, notion: Mainstream journalism exists to maintain the status quo. And graphic images of war are allowed to be printed and broadcast precisely because at the end of the viewing, the status quo will likely be maintained. Here is what photography blogger Hugh McCabe in the blog Traces of the Real says, quoting art critic and writer John Berger:

Shocking images [of war]… had only recently become acceptable in American newspapers and (John) Berger recounts two commonly cited reasons for this. One is that the public are demanding to know the truth of war and the newspapers are giving them what they want. The second is that the public have steadily become immune to images of horror and the newspapers are competing to show ever more horrific images in order to gain their attention. Berger rejects both of these, and goes on to suggest that such images are now acceptable to the mainstream media because they are clearly failing to have their intended effect. By this he means that they are not moving the public to seriously question, challenge or threaten the political establishment that is pursuing the war. If they did, then the media would not be carrying them.