Amazon does not publish any “tolerance” like “97% of pixels may be off-white.” The rule is simply: the main image background must be pure white, RGB 255,255,255.
In practice, that means:
If the background contains visible gray, color casts, gradients, or strong shadows, Amazon can treat it as non‑pure white and reject or suppress the image.
Most professional guides recommend treating the entire background as 100% pure white and checking it with an eyedropper, rather than relying on any assumed tolerance.
So the safe approach for 2026 is to assume zero tolerance: every background pixel should be pure white wherever it’s visible behind the product.