If you go into the kids section, the girl is pictured without the t shirt and her right thigh looks bigger in the other picture, so it may have been airbrushed.
The airbrushing of children's pictures should definitely not be allowed.
Also, i don't think that using terms such as, slim and fat are helpful for children, some are chunkier, or rather bigger framed. As long as they are in normal limits, "small" etc, would be better.
Carrying body fat, excessively and being bigger framed/built are two different things.