Allegro photo requirements and the pure white rule

Allegro is stricter about the first photo than almost any seller realises, and it does not send you a warning email when you get it wrong. It simply lets your offer perform worse than it should.

The rules, exactly

• Background. The thumbnail, meaning the first photo of the offer, must sit on uniform white with the value RGB 255,255,255. Not cream, not light grey, not the white wall in your office. A photo taken in a cheap light tent is almost never pure white; it lands somewhere near 240 with a blue cast, and the check sees the difference even though your eye does not.
• Size. Longer side between 400 and 2560 pixels, up to 26 megapixels. Anything larger gets downscaled by Allegro, which costs sharpness, so exporting at exactly 2560 x 2560 gives you the sharpest legal image.
• Format and colour. JPG or PNG, sRGB colour profile. If you shoot in Adobe RGB and never convert, your reds go flat on the buyer's screen.
• Nothing added. No frames, no borders, no text, no logos, no watermarks, no collages on the thumbnail. Allegro wants the product, alone, on white.

The grey exception nobody knows about

Allegro allows a uniform light grey instead of white, but only in selected Fashion, Kids and Sport subcategories, and it defines the allowed grey in the HSV colour model with brightness V of at least 0.8. In plain terms: light enough that it still reads as a studio background rather than a colour. The preset called Allegro fashion grey in this tool uses #EBEBEB, which sits at V = 0.92, comfortably inside the rule. If you sell shoes, clothing or sports gear, grey often makes a black product read better than white does, because a black boot on pure white loses its own outline.

Why sellers lose money here quietly

Allegro search results are a wall of thumbnails. Buyers do not read titles first; they scan images and stop at the one that looks like a shop rather than a kitchen table. A grey-white background, a shadow in the corner, a visible edge of a light tent: each costs you a fraction of a percent of clicks, and a fraction of a percent across thousands of impressions is real money. The pure white rule is not bureaucracy. It is Allegro forcing a consistent grid so buyers compare products instead of photography.

Tips that separate a good listing from a great one

• Fill the frame. Allegro does not enforce a fill percentage, but a product floating in the middle of a big white square looks weak beside a competitor who fills it. Aim for the product taking roughly 85 percent of the longer side. This tool defaults to 86 percent.
• Square everything. Allegro shows thumbnails in a square crop. Give it a square and you control what gets cut. Give it a portrait photo and Allegro decides for you.
• White thumbnail, real life afterwards. The first photo must be clean and white. Photos two onwards can and should show the product in use, in a hand, next to a coin for scale. That is where you sell.
• Scale is trust. The most common cause of a return is a buyer expecting a different size. One photo with a clear reference object prevents more returns than any description ever will.
• 2560, always. Buyers on desktop zoom. A 2560 image lets them see stitching, grain and finish. An 800 pixel image tells them you are careless.

The fastest way to comply

Remove the background entirely and paint a true 255,255,255 behind the product. That is the only method that hits the value exactly every time, regardless of your lighting, your camera or your room. Everything else is a guess with a colour picker. Pick the Allegro 2560 white preset here and it is done in about two seconds per photo, for as many photos as you want, free.

Open the free tool and drop your photos in. Pick the preset for your platform, download one ZIP, done. No account, no limit, and the photos never leave your computer.