Many people in the make up industry use Photoshop to promote their products. This one may have been touched up to make the lips shinier and have brighter colours. The creator would want customers to think that it will make their lips as shiny as the woman on the advert. It is aimed at women that care a lot about their appearance, and people who want to be 'glamorous' as it is called GlamShine. It would be effective to people wanting shiny colourful lips, as those people might buy the product.
This product is designed to make your skin have a richer colour and cover up any spots, blemishes or similar things. The creator wants people to think it will make you have perfect skin. It is aimed at people who have something like a spot problem and want to cover up their actual skin. They Photoshopped this image so that the skin appears smoother and brighter than it actually is. It was effective for a while, getting people to believe it but then the image went under fire for changing the truth.
Photoshop has a dark side to it...
~Ian