Shelf facing study -- image sizes

I'm designing a shelf facing study with 6 shelves and 6 SKUs on each shelf.

What is the best size for the shelf images? Plus, the images will be enlarged when hovered over. What is the best size for the enlarged images that will then pop-up?

Knowing this will save time on readjusting the images to make them just right after obtaining them. I'd rather give the photographer the specs and have the right sizes to place into the CBC.

Thanks to anyone who answers.

Resolved