Because they can?
It appears someone figured out Photoshop. The babies left ear was not taken very cleanly from the original image, and the candies look huge compared to the baby, but otherwise it is believably done.
The bad idea part of this is that someone will think the photo was done in camera and will try to stuff a baby into a tub full of candies and suffocate the baby. It is amazing to me but evidence suggests most people don’t realize the images they see in magazines are airbrushed/photoshopped. They think if it is in a photo it must be true.