Free tool · no signup · no upload
Compress JPEG images
Shrink JPEGs 40–70% with no visible quality loss — unlimited files, right in your browser with MozJPEG. Nothing gets uploaded.
Drop a JPEG — up to 70% smaller, same look. Captioned; no sound needed.
Drop images here or click to choose
JPG, PNG, HEIC — as many as you like
🔒 Conversion happens entirely on your device via WebAssembly — files are never uploaded, stored, or seen by anyone. HEIC decoding uses libheif (LGPL).
Why unlimited and free?
Compression services meter you because your images run through their servers. Here, MozJPEG — Mozilla's open-source encoder, compiled to WebAssembly — runs on your computer instead. No server costs, no credits, and your photos stay private by construction.
Built by PrinterFlo, print shop management software. Also try: WebP & AVIF converter · PNG compressor · HEIC to JPG
Frequently asked questions
How can it compress a JPEG without losing quality?
Strictly speaking every JPEG re-encode is lossy — but at quality 75–85 the differences are invisible to the human eye while the file often shrinks 40–70%. This tool uses MozJPEG, Mozilla's encoder tuned specifically to maximize visual quality per byte — the same engine behind professional optimization services.
Is there a file size or count limit?
None. The compression runs on your own computer via WebAssembly, so there's no server to pay for and nothing to meter. Compress one photo or a thousand.
Are my photos uploaded?
No — files never leave your device. The encoder runs locally in your browser; we can't see, store or transmit your images.
What quality setting should I use?
80 (the default) is right for almost everything. Use 85–90 for photography you'll look at closely, 70–75 for web page images where speed matters most. Below 60 you'll start seeing artifacts in gradients and skin tones.
Should I use WebP or AVIF instead of JPEG?
If the image is going on a website, yes — WebP is ~25–35% smaller and AVIF ~30–50% smaller than an equivalent JPEG, and every modern browser supports both. This tool converts to either; keep JPEG when you need universal compatibility (email, old software, print services).
Can it compress PNG too?
Yes — pick the PNG output for lossless PNG optimization (pixels stay bit-identical, the file still shrinks), or convert PNGs to WebP/AVIF for much bigger savings on photos.
More free tools: printerflo.com/tools