Walmart could not download or validate your product image. The listing may go live without an image, but it won't appear in search and conversion will collapse.
Common causes: 404 image URL, an HTTP redirect chain longer than 3 hops, image hosted on a domain Walmart's crawler can't reach, image-format mismatch (Walmart needs JPG/PNG, no WebP/SVG), or image below the 1500-pixel longest-edge minimum.