Will your main image pass? Check the photo itself.
Choose a marketplace and drop a product photo. The checker measures the background, how much of the frame the product fills, whether it touches an edge and whether it casts a shadow, then compares each measurement with the marketplace's published rule. It runs in your browser; nothing is uploaded.
Choose a marketplace and a photo.
Rules come from each marketplace's own help pages, summarised in the guides (checked 24 September 2026). Size, file size and format are checked as well.
How each rule is measured.
- Background colour
- The background colour is the median of a thin band along all four edges. A pure-white rule passes only when that band is RGB 255, 255, 255; near-white values such as 253 are reported with their exact colour.
- Product fill
- The product is separated from a plain background by growing the background inwards from the edges until the colour changes sharply. Fill is the product's share of the frame on its longest axis, the way Amazon's 85% and Google's 75–90% rules are read.
- Cut-off edges
- A product whose outline reaches the edge of the frame is reported as cut off, together with the edges it touches.
- Shadows
- Pixels next to the product that are darker than the background, but not part of the product, are reported as a shadow.
- Square format
- Width and height must match to within 2%.
- Thumbnail crops
- The product must fit inside centred square, 4:5 portrait and 5:4 landscape crops of the photo.
- Scene photos
- Room and lifestyle photos have no plain background to measure against, so fill, edges and shadow are marked as not measured rather than guessed.
Checkers by marketplace.
About the checker.
Is my image uploaded?
No. The file is read and processed inside your browser; nothing is sent to a server.
Why is fill not measured on my lifestyle photo?
Fill needs a plain background to separate the product from. On a room or table scene the checker says so instead of guessing a number. Marketplaces that set a fill rule apply it to the main image, which is normally shot on a plain background.
How accurate is the measurement?
The photo is measured at 640 pixels on its longest side, so fill is accurate to about one percentage point. A white product on a white background can blend into it; the outline drawn on the preview shows what was measured.
What if my photo fails?
Herofab creates on-model, ghost-mannequin and white-background images from one product photo. Join the waitlist to try it with 20 free credits.
Image size checker
Size, file size, format and aspect ratio, checked against each marketplace's published rules.
Free · in your browser→Marketplace image resizer
Fit a photo to your marketplace's dimensions — padded, never cropped.
Free · in your browser→HEIC to JPG converter
Turn iPhone HEIC photos into JPGs that every marketplace accepts.
Free · in your browser→White background checker
Measure whether the edges of a packshot are pure white #FFFFFF.
Free · in your browser→AI image label checker
See whether a product image still carries its AI marker: IPTC source type, the keyword for AI-generated people and C2PA credentials.
Free · in your browser→Your next collection, shot this week.
20 free credits when early access opens. No card required.