Your images are read locally by the browser and measured on a canvas. No file is sent to us or to anyone else, which is also why the check is instant and handles a folder of two hundred photos without a progress bar.
| Amazon | At least 1,000 px on the longest side so zoom works; 2,000 px recommended. Main image on a pure white background (RGB 255,255,255), with the product filling about 85% of the frame. Up to 10 MB. |
| Walmart | Strictly 1:1 square. Below 500 × 500 px the listing is unpublished automatically; 1,500 × 1,500 px unlocks zoom, and 2,200 × 2,200 px is recommended. Pure white background on the primary image. Up to 5 MB. |
| eBay | Minimum 500 px on the longest side; 1,600 px recommended so zoom is enabled. Up to 7 MB. A white background is recommended but not enforced. |
| Allegro | Minimum 500 px on each side. Larger is better — Allegro generates its own thumbnails, and a small source looks soft in the results grid. |
| Etsy | 2,000 px on the shortest side recommended, but each file is capped at 1 MB — the tightest weight limit of any major channel. No background requirement; lifestyle shots typically outperform white-background studio images. |
| Kaufland | Target output 2,048 × 2,048 px, so the source should have at least 1,024 px on the longest side to avoid upscaling. |
| OTTO | Square main image on a white background. File names must not contain umlauts or special characters — a common cause of failed imports. |
| Zalando | JPEG only, portrait ratio 1:1.44. Listings are rejected outright if the minimum image count is not met. The strictest fashion channel in Europe. |
| Shopify | Renders sharply up to 2,048 × 2,048 px, with a generous 20 MB file limit — but keeping files under 500 KB is what protects your Core Web Vitals. |
No single file satisfies every channel. A 2,048 × 2,048 px square JPEG on white, kept under 1 MB, passes Amazon, Walmart, eBay, Allegro, Kaufland, OTTO and Shopify, and squeezes under Etsy's weight cap. Zalando always needs its own portrait crop. Shoot at 2,200 px or above and derive the rest — upscaling never recovers detail.
The tool samples the four corners of each image. If at least three are near-white, the background is treated as white. That catches the common failure — a grey studio sweep or a lifestyle shot used as the main image — but it is a heuristic, not a verdict. A product photographed on white with heavy vignetting can fail the corner test and still be accepted, and the reverse happens too.
Image rejections surface days after a bulk upload, one listing at a time, and every fix means going back to the source files. Checking the folder first takes a minute. Preparing a full catalogue to each channel's spec is part of Listing Production.