A white background does two things for jewelry: it removes distraction so the piece reads at thumbnail size, and it makes every listing in a grid look like part of the same catalog. That is why marketplaces built around search results care about it most.
The strictness varies. Amazon’s main image is the strictest case: as widely reported, the background must be pure white and the product must fill most of the frame. Etsy has no white-background rule, but since its October 2026 update it requires most listings to include one real, unedited photo, which is often taken on a real surface rather than white. Shopify stores set their own style.
“White” also means different things. To a person, cream and light gray can look white. To an automated check, only RGB 255, 255, 255 is pure white. If a platform requires white, measure it rather than eyeballing it.