Two shops can photograph the same mug with the same camera, and one listing looks crisp while the other looks faintly smeared. The difference is rarely the camera. It is what happens between the camera and the screen: cropping, resizing, compression and the way the platform displays the result. This guide walks through those steps so your product photos arrive sharp everywhere.
Pixels, not inches
On screens, only pixel dimensions matter. The “DPI” or “PPI” value stored in a file affects printing, but a 2000 × 2000 image set to 72 DPI and the same image set to 300 DPI look identical in a browser. When a platform asks for “high resolution”, it means enough pixels.
How many is enough depends on the largest size at which the image will appear, multiplied by the screen's pixel density. A product image shown 600 CSS pixels wide on a phone with a 3× display needs 1800 real pixels to be drawn without upscaling. Add room for zoom, and the numbers marketplaces recommend start to make sense.
What the platforms ask for
Each marketplace publishes its own guidance, and those pages change. At the time of our last check, Amazon required images to be at least 1000 pixels on the longest side for zoom to work; Shopify suggested 2048 × 2048 for square product images; eBay required at least 500 pixels on the longest side and recommended 1600. Most feed-based social platforms display images at around 1080 pixels wide. Treat these as a starting point and confirm them in each platform's help centre before preparing a large catalogue.
A practical approach: keep one high-resolution master of every product shot (the camera original, or at least 3000 pixels on the long side) and generate channel-specific versions from it. Never generate a large version from a small one.
Square is the safe default
Many storefront themes and marketplace search grids crop images to a square thumbnail. If your photo is 3:2, the theme decides what to cut, and it may cut the handle off your mug. Cropping to 1:1 yourself keeps control of the composition. For portrait products like bottles or clothing on a model, 4:5 is a good alternative that still displays well in square grids with modest cropping.
Leave breathing room. A product that touches the edges of the frame looks cramped in a grid, and some platforms ask for the product to fill a specific share of the image. Something like 80–90% of the frame is a common target.
Why resized images go soft
Upscaling
Enlarging an image cannot create detail; the software has to invent in-between pixels by interpolation, and the result looks blurry. If a platform needs 2000 pixels and your photo is 1200, the honest options are to reshoot, or to accept a smaller zoom.
Downscaling in one big step
Shrinking a 6000-pixel photo to 1000 pixels in a single pass can skip over source pixels, producing jagged edges and shimmering patterns in fabric and mesh (moiré). Good resizers average neighbouring pixels properly or step down in halves. If your edges look jagged after resizing, this is the likely cause.
Platform recompression
Most platforms re-encode what you upload. If you upload a heavily compressed file, it gets compressed twice and artefacts compound. Upload at high quality and at the recommended dimensions, and let the platform make its own smaller copies.
Sharpness versus file size
Your own website is different from a marketplace: there you are responsible for loading speed. A gallery of 4 MB images makes pages slow on mobile connections, and slow product pages lose visitors. The aim is the smallest file that still looks sharp at the size displayed.
- Resize to the largest size the image is actually displayed at, times two for high-density screens. 1600–2000 pixels covers most product pages with zoom.
- Choose a modern format. Lossy WebP is a strong default for photos.
- Set a file-size budget — 150 to 300 KB is a reasonable range for a main gallery image — and find the highest quality that fits.
- Inspect the result at 100% zoom. Look at fine texture, text on packaging, and smooth gradients in the background.
Dimensions dominate file size. Halving the width and height reduces the pixel count to a quarter, which shrinks the file much more than any reasonable change in quality setting.
Backgrounds and consistency
Pure white backgrounds are expected by several large marketplaces for main images, and they make a catalogue look consistent. When padding a non-square image to a square, pad with the same white as the photo's background; an off-white photo padded with pure white shows a visible seam.
If you have a cut-out product with a transparent background, decide where it will live. Transparency is supported on your own site in PNG or WebP, but many marketplaces flatten it, so supply the white version yourself rather than leaving the result to chance.
Before you upload: a checklist
- Cropped deliberately, with the product centred and a little margin.
- Resized down from a larger master, never up.
- Dimensions match or exceed the platform's current recommendation.
- Saved at high quality for marketplaces; size-budgeted for your own site.
- Background matches the platform's requirement.
- Metadata reviewed: exporting through a canvas-based tool drops EXIF data, including the GPS location that phone cameras often record.
Summary
Sharp product photos come from a simple discipline: start from a large original, crop for the grid, resize down in one controlled step, compress to a budget, and check the result at full size. Platform specs will keep changing, but the logic behind them — enough real pixels for the largest display, without wasting bandwidth — stays the same.