Snap recommends a 1080x1920 9:16 vertical image for catalog products that render in story-format placements. Lower-resolution sources upscale poorly and fail Snap's quality review for full-screen creative.
Snap Catalog Manager requires product images that are publicly reachable, sized within the platform's bounds, in supported formats (JPEG/PNG typically), and free of overlays, watermarks, retailer logos, or text callouts. This issue trips when one of those constraints is broken.