About CompressLocal

CompressLocal is a free image compression tool that works entirely in your browser. No sign-ups, no uploads, no servers processing your files. You pick a target file size, drop your images, and download the compressed versions — all without a single byte leaving your device.

Why we built this

Most image compressors upload your files to a remote server. That means your photos, screenshots, and documents pass through someone else's infrastructure. We wanted a tool that gives you the same results without the privacy trade-off.

Whether you're compressing sensitive screenshots at work, preparing photos for a client, or optimizing images for your blog, you shouldn't have to wonder who else can see your files. With CompressLocal, the answer is always "nobody" — because your images literally never leave your computer.

How it works

Under the hood, CompressLocal uses the browser's built-in Canvas API and Web Workers to re-encode images at progressively lower quality levels until they fit under your target size. Three images process concurrently to balance speed and memory. The entire process runs in background threads so the UI stays responsive.

For PNG files, which are lossless and don't respond to quality-based compression, the tool internally converts them to WebP format to achieve meaningful size reduction. The output file keeps the original .png extension so it works everywhere you need it.

Supported formats

• JPEG — Quality-based compression, great for photographs and complex images with gradients
• PNG — Internally converted to WebP for effective compression, saved with the original .png extension
• WebP — Modern format with excellent compression ratios, supported by all major browsers since 2020

More than just compression

CompressLocal also includes a suite of free image tools, all running 100% in your browser:

• Format converter — Switch between JPG, PNG, and WebP with adjustable quality
• Image resizer — Resize by width, exact dimensions, or percentage with aspect ratio lock
• Image to PDF — Merge multiple images into a single PDF with reordering and page size options

Tech stack

Built with Next.js, Tailwind CSS, and the browser-image-compression library. Deployed as a fully static site on AWS CloudFront. There are zero API routes and zero server-side processing — the entire site is just HTML, CSS, and JavaScript served from a CDN.

Privacy by design

This isn't just a marketing claim. The architecture makes it physically impossible for us to access your images. There is no server to receive uploads, no database to store files, and no API endpoint that handles image data. The static site is served from a CDN and all processing happens in your browser's sandbox.

Don't take our word for it — open DevTools while compressing and check the Network tab. You'll see zero outgoing requests carrying your image data. That's the whole point.

Common use cases