Photoshopping is using a special computer program that manipulates a photo to alter its appearance. Models that appear on magazine covers often have their pictures photoshopped to make them look more attractive than they really are (according to some standard of beauty held in most of the Western world, but not a universal one).
This unethical practice has been criticized for giving most girls a terrible self image by making them compare their imperfect bodies to what they see in magazines. A similar argument has been made about Barbie dolls, with their unrealistic body proportions, but at least pictures of Barbie dolls are not photoshopped. Doing that to actual human models should be considered fraud. And fraud IS illegal, so it is not a stretch to outlaw photoshopping and require all magazines, newspapers, and news websites to only publish pictures that are not photoshopped. We should be able to see what is real, not someone’s idea of beauty that is not real!