[Clamchop]

In the US, photos of food must depict the actual product being advertised. So all the photos of burgers on the McD's menu are what is being sold, albeit with carefully selected "hero" ingredients skillfully assembled for the best presentation.

For a product that is only advertising one thing in a photo, e.g. an ice cream cone with ice cream on a package of just cones, I don't think there are any restrictions on what the "ice cream" can be made of. (It's probably mashed potatoes, though.)