Amazon sets the best-known rules for the main image: a pure white background (RGB 255, 255, 255), the product filling about 85% of the frame, and no props, text or extra items. Images 1,000 pixels or larger on the longest side let shoppers zoom. A main image that breaks the rules can keep a listing out of search.
Pure white is harder than it sounds. Light grey reads as dirty, a missing shadow makes the product float, and white or cream products vanish into the background. The packshot entry covers lighting the product itself; here the test is the background value and the edges.
