I still don't think it is right. Look at the areas of lightness. Why fake lightness, unless it is a mushroom shape he was going for?
I don't know what you mean by "areas of lightness," and it's not easy to do any sophisticated photo analysis on a low-resolution, heavily compressed version of the image from Yahoo. If there were any shenanigans on the refed photo, it's subtle enough that it would take a higher-res, less-compressed version to nail down.
Sorry, but I still don't see the argument for bias or the motive here. Why risk your job to make a cloud of smoke look vaguely more mushroom shaped? I don't doubt the widespread existence of bias in the media (several different biases, actually), but some of the arguments are reminiscent of the folks looking for skull-shapes in the ice cubes in liquor ads.
If I'm ever stunningly wealthy- I'll buy Reuters and mandate that the only image manipulation that will be done on the product, will be done with MS Paint.
It'd look like a kid drew a mushroom cloud with crayons.