Despite the great improvement of the recent versions of nopcommerce, I think it still lacks some functionalities, especially for clothing type of products.
Usually in clothing you have color and size variant of the same product. Most of a time you want to have picture of the product from different angles or different details.
If you have a color variant you would like to show the same pictures but for the different color version.
Currently this is not possible in nopcommerce (unless I miss something), because product attributes only support one picture at the time.
With grouped products doesn't work either, since the product in the ProductTemplateGrouped doesn't show more than one picture.
this is a link of the functionality I'm talking about, select a different color to see what happens
http://demo.commerceguys.com/ck/tops/guy-hoodie
and this where you can see the color variant from the product grid
http://store.nike.com/it/it_it/pw/uomo-t-shirts-abbigliamento/7puZbgdZbhk
and the details page
http://store.nike.com/it/it_it/pd/miler-uv-maglia-running/pid-709533/pgid-676228
PS. great job so far