CNN has started reporting on the situation in Iran. They have described some of the pictures on the Internet, but also put in a disclaimer about them, saying they are establishing independent confirmation. This is a direct result of the problems they had in the past accepting any source based more on its sensational value rather than its authenticity.

Then there is this from Andrew at the Dish. He links to this, although he prefaces it with the fact that he can't confirm the credentials of the source.

In my opinion, this is irresponsible at best. If you can't vet the source, it shouldn't be used, because its use can only be for its sensational value, everything else being meaningless due to a lack of credibility.