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WASM Image Optimizer

Optimize images using MozJPEG, WebP, AVIF, and OxiPNG WASM codecs running entirely in your browser. Compare compression results side-by-side and download the smallest file.

FreeNo SignupNo Server UploadsZero Tracking

100% Private

Your files never leave your browser. All processing happens locally on your device.

Powered by WebAssembly

Drop an image here or click to browse

Supports JPEG, PNG, WebP -- encodes through 4 WASM codecs simultaneously

Why WASM codecs produce smaller images

Browsers' built-in Canvas.toBlob() uses a basic JPEG/PNG/WebP encoder optimized for speed, not file size. The WASM codecs used here are the same production-grade encoders used by CDNs and image optimization services:

All processing runs locally via WebAssembly. Your images are never uploaded.

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How to Use WASM Image Optimizer

  1. 1

    Upload an image

    Drag and drop a JPEG, PNG, or WebP image, or click to browse your files.

  2. 2

    Set quality

    Adjust the quality slider (1-100) for lossy codecs. OxiPNG runs lossless automatically.

  3. 3

    Optimize

    Click Optimize to encode your image through all 4 WASM codecs simultaneously — MozJPEG, WebP, AVIF, and OxiPNG.

  4. 4

    Compare results

    Review the file size, compression ratio, and processing time for each codec side-by-side.

  5. 5

    Download

    Download the format that gives you the best size-to-quality ratio. The smallest result is highlighted with a Best badge.

Frequently Asked Questions

WebAssembly (WASM) lets us run production-grade image codecs like MozJPEG, WebP, AVIF, and OxiPNG directly in your browser. These are the same codecs used by Google's Squoosh — they produce significantly smaller files than the browser's built-in Canvas API.

The standard Image Compressor uses your browser's built-in Canvas.toBlob() API. This WASM Optimizer uses dedicated codec libraries (via jSquash) that can produce 20-40% smaller files at the same visual quality, and supports AVIF output which Canvas cannot.

No. All encoding happens locally in your browser using WebAssembly modules. Your images never leave your device.

AVIF uses the AV1 codec which is computationally more intensive. It produces the smallest files but takes longer to encode. MozJPEG and WebP are faster alternatives with excellent compression.

You can upload JPEG, PNG, and WebP images. The tool will encode your image into all four output formats (MozJPEG JPEG, WebP, AVIF, and optimized PNG) so you can compare and pick the best one.

Each codec loads independently. If one fails (for example, AVIF may not work in older browsers), the other codecs will still process your image. Failed codecs show a 'Not available' message.

There is no hard limit, but WASM codecs are more memory-intensive than Canvas. For best performance, keep images under 20 MP (e.g. 5000x4000 pixels).