How-to

How to resize images for marketplace upload

Resize product images from the original file. Match pixel minimums and aspect ratios for each channel, then compress. Do not upscale a small photo.

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Steps

  1. Open the master, not a thumbnail

    Use the camera or design export. A collection thumb is already too small to become a zoomable main image.

  2. Set longest side and aspect for one channel

    In Image Resizer, pick the Amazon, Shopify or TikTok Shop target you are filling today. Keep catalog aspect consistent (1:1 vs 3:4). Do not auto-stretch to force a square.

  3. Export, then compress

    Save the resized file, then open Image Compressor. Zoom edges and type at 100%. If the file is still huge, you probably skipped the pixel step.

  4. Name the file by SKU and channel

    Use names like sku_amazon_main.jpg and sku_shopify_pdp.jpg. The names prevent uploading a 9:16 video crop as an Amazon main image.

Pixels and aspect, not print DPI

On the web, pixel dimensions matter more than a 300 DPI tag. Read current size guidance for that channel; minimums change. White-background rules are separate from pixel counts. Work from the original. A longest side of about 1600–2500 px often covers zoom without giant files.

One original, several exports

A phone photo can become an Amazon square white main, a Shopify long-side export that matches the theme, and a 9:16 cover crop for video. Do not crop out required white space on an Amazon main image; lifestyle crops belong in secondary slots. CrossKit Image Resizer sets dimensions in the browser; Image Compressor then reduces weight.

Never upscale a small photo

Stretching 600 px to 2000 px does not create detail—it enlarges artifacts. Reshoot or accept a smaller display. Sort mixed aspect ratios before a batch; auto-stretch breaks collection grids. Name files by SKU and channel so the wrong crop does not land in the main slot.

Compress after resize

Pixels first, quality second. Marketplace catalog slots usually want JPEG or PNG that meet current minimums. CrossKit does not upload for you and does not invent a partnership badge with any marketplace.

Related CrossKit tool

Image Resizer

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FAQ

Frequently Asked Questions

Should every marketplace get the same pixel size?

No. One-size exports either waste bytes or fail a minimum. Export per channel from the same master.

Can I batch resize mixed aspect ratios?

You can, but collection grids will look broken. Sort by aspect, then batch. Do not auto-stretch.

Does Image Resizer upload to Amazon or Shopify?

No. It prepares files in the browser. You upload the export in Seller Central or Shopify admin.

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