Without photography, most of the resources of evidence would be non existent. The most reliable resource of evidence is a photograph, or is it? Nowadays, manipulating images has become incredibly easy, so people have become more skeptical when seeing pictures in newspapers or magazine articles. Pictures aren't only used as proof, but also to create an image. For example, advertisers doctor their images in order for them to look more professional and attractive.
This lecture reminded me of the importance of photography
A good website I found on how photography works as evidence is: http://www.seanet.com/~rod/digiphot.html. It explains the different levels how images are manipulated and used to prove the truth or tell a lie.