Looks rather like this mushroom cloud:
Not saying it's impossible for both clouds to be from the same nuclear test, just that it's unlikely two photographs, taken at different distances and presumably at different times, would depict the same
mushroom cloud. Also, the mountains and terrain look different, and frankly it's unlikely that the kids and the photographer could have gotten that close to a nuclear test or that the camera (not to mention the kids and the photographer) would have survived (maybe the film developed itself).
But I still say that kid looks funny.