Most "free" image compressors upload your files to a server, cap you at 10 images, or watermark your output. I wanted something different.

So I compiled Mozilla's mozJPEG, Google's libwebp, and libaom (AVIF) to WebAssembly using Emscripten. Each image compresses on a separate Web Worker, saturating all CPU cores. On an 8-core laptop, 8 images compress simultaneously. A batch of 200 photos finishes in seconds.

No uploads. No limits. No data ever leaves your device.

Try it: https://toolboximage.com