Updated
A skincare shopper can't feel the cream or smell the serum, so the photo has to show how it behaves: how thick it is, how it spreads, how it sits on skin. Texture shots, finger-swipes and drops do the work a tester does in a shop.
Skincare is also claim-sensitive. Labels carry ingredient names and certifications that have to read clearly, and images must never suggest results the product hasn't been shown to deliver.