I built a 100% client-side image resizer for marketplace sellers (no upload, no server)
If you've ever listed anything on Etsy, you know the ritual: resize to 2000×2000, pad onto a white square, compress under 1MB, export as JPG — times 40 listings. Most people do this by hand in Photoshop or some sketchy online converter that uploads their product photos to who-knows-where. I got tired of both, so I built a small tool that runs entirely in the browser:…
Tired of manually resizing and compressing product photos for multiple online marketplaces, a developer created an entirely browser-based tool to simplify the process. This image resizer works without any server or uploads, meaning photos are handled locally on the user's device. The tool offers presets for popular platforms like Etsy, Amazon, eBay, Shopify, Depop, Mercari, and Walmart, allowing users to resize images to the required dimensions in just a few clicks.
Two resizing modes are available: padding the image onto a white square or center-cropping the photo to cover the entire space. Users can also manually adjust the crop, with a drag-and-zoom feature and keyboard nudging for precision. The tool includes a HEIC input option for iPhone users, converting the images to a more widely compatible format while maintaining the desired quality.
Instead of a fixed quality slider, the tool uses a binary search approach to find the optimal JPEG quality that ensures the final size is under one megabyte. Users input their target size, and the tool automatically adjusts the image quality until it meets the requirement. This feature saves time and eliminates the guesswork involved in determining the perfect quality setting.
The background tab safety feature ensures that the tool remains responsive, even when the browser tab is inactive. It uses the requestAnimationFrame API to control the image processing, pausing automatically when the tab is in the background. If necessary, a setInterval fallback is employed to maintain functionality during these instances.
Currently, the tool supports seven marketplaces simultaneously, covering the most common requirements for sellers across various platforms. However, the developer plans to expand the preset coverage further and potentially introduce Progressive Web App (PWA) mode to enhance accessibility and user experience. If you sell on a platform not currently supported, the developer invites feedback and suggestions to add new presets.
The source code for the project is available on GitHub under the MIT license, enabling users to explore the code and contribute to the tool's development. The live demo can be accessed at https://etsy-image-resizers.netlify.app/. Feedback is welcome, particularly on the crop editor's user experience and whether the preset list needs to be expanded to include other popular platforms like Poshmark or Vinted.
Written by urgent.news from Dev.to's reporting — not their text. Machine-written — may contain errors; check the original before relying on it.
