Journalists can use photo manipulation in various ways. Subtle alterations can be used to simply enhance the quality of the photograph, such as adjusting lighting and coloration, which typically does not change the overall message of the story. In other cases, journalists can manipulate their photos in order to propagandise them to sway the opinion of their readers in a particular direction.
Manipulation techniques have been used for decades in journalistic photography. Below is an example of how photo manipulation in journalism has been used to create propaganda.
The original photo is on


The next image shows an original photo and the altered version of Jaques Steinberg, a New York Times reporter, who was accused by Fox News of writing attack stories about them.

a message that this man is a hideous human being trying to cause damage to Fox News, and by making him look like more of an ogre it creates much more of an impact then his actual appearance would. This can be seen as a form of modern day propaganda used by journalists.
References:
http://en.wikipedia.org/wiki/Photo_manipulation
http://mediamatters.org/research/200807020002
http://www.youtube.com/watch?v=lCHrd5q9Kcc