He is talking about post-click manipulation. Consumers bring their own assumptions to perception of images and do not see them in the same ways. Some people are more sophisticated in their understanding of manipulation, e.g., the Texas Monthly covers of Ann Richards. Some journalists think that photo manipulation threatens the credibility of non-manipulated photos because people don't know what to believe anymore. Journalists sometimes apply different photo standards to covers because they are marketing tools, e.g., taking Kate Moss' nipples off a cover photo but leaving them in an inside photo.
Disclaimers present other kinds of problems.
Both were based on the same mug shot taken by the police but manipulated quite differently and had different messages typed across them. Think about the communication models that we reviewed, especially the critical ones. If not then the issue of disclosure is raised.