Browser tool

Image Resizer

Use PolyImg’s online image resizer to scale photos for web, mobile, and ads entirely in your browser—no uploads, no waiting on server queues, perfect for “resize image for Instagram” requests, Shopify product grids, and newsletter hero shots.

Capabilities

Resize once, ship everywhere

Responsive presets

Resize images for hero banners, thumbnails, social ratios, and multi-breakpoint layouts with reusable templates.

Batch image resizer

Drop entire folders or drag hundreds of assets—the PolyImg image resizer scales each file locally without throttling.

Browser-only workflow

All resizing happens via Canvas, OffscreenCanvas, and WebAssembly so sensitive photos never leave your device.

WebAssembly-powered scaling mirrors what CDNs deliver, so what you preview locally is what users load in production.
Workflow

Three steps to perfectly sized assets

  1. 1Upload or drop any mix of JPG, PNG, WEBP, GIF, HEIC, or SVG files into the workspace.
  2. 2Pick a preset (e.g., 2048px hero, 1080x1080 square) or type exact dimensions/percentages and preview results instantly.
  3. 3Export downsized images in bulk or copy them straight to your CMS or design system.
  • Apply multiple presets at once (e.g., 3 hero sizes + thumbnail) and export them together for responsive sites.
  • Save preferred presets to IndexedDB, ensuring every teammate resizes assets the same way.
Quality & privacy

Keep quality high without sacrificing privacy

PolyImg’s resizing algorithms respect sharp edges, gradients, and transparency so UI screens, ecommerce shots, and social graphics remain crisp.

Because the online image resizer never uploads files, unreleased campaigns, compliance documents, or patient imagery stay secure end to end.

FAQs

Frequent questions about the PolyImg image resizer. Need automation or API workflows? Reach out.