And it does speak to a larger issue which is when photo manipulations reach a point where photos can no longer be trusted to be what they represent. In truth, this has always been the case with careful cropping and framing you can mislead someone into thinking that something in the photo happened that isn't accurate. But the Photoshop crowd can really take it to extremes.
Personally, I enjoy the photo parodies as long as it is clear that this is what they are and not attempts to deceive the public. Just as with other forms of comedy, photo parodies are given wide latitude for public figures or current events. However, there should be a serious recognition by parties who create and publish photos that the integrity of photojournalism must be maintained or we will all suffer the consequences. It's hard enough to convince some people to believe the truth without giving them the easy out of claiming photographs are faked or doctored.
In the digital age it's viewer / reader beware. These days we all have the capacity to be reporters a la Drudge ... or photo editors. Remember the early days of the Internet where we were all urged to dismiss news gathered online since you never knew if it was true. Well, we all just have to be more skeptical when we read that Sid Bluminthal beat his wife ... or Kerry stood with Jane.
The onus was on the "legitimate" news sources for not vetting the photo before going to press with it. They are the ones shirking responsiblity. Doctored photos have always been a possibility.