MozJPEG reduces file sizes of JPEG images while retaining quality and compatibility with the vast majority of the world's deployed decoders.

MozJPEG is based on libjpeg-turbo. It's compatible with libjpeg API and ABI, and can be used as a drop-in replacement for libjpeg. MozJPEG makes tradeoffs that are intended to benefit Web use cases and focuses solely on improving encoding, so it's best used as part of a Web encoding workflow.

MozJPEG is meant to be used as a library in graphics programs and image processing tools. We include a demo cjpeg tool, but it's not intended for serious use. We encourage authors of graphics programs to use MozJPEG's C API instead.

• Progressive encoding with "jpegrescan" optimization. It can be applied to any JPEG file (with jpegtran) to losslessly reduce file size.
• Trellis quantization. When converting other formats to JPEG it maximizes quality/filesize ratio.
• Comes with new quantization table presets, e.g. tuned for high-resolution displays.
• Fully compatible with all web browsers.
• Can be seamlessly integrated into any program using libjpeg.

• Latest release
• Version 3.0 Announcement (overview of 3.0 features)
• Version 2.0 Announcement
• Version 1.0 Announcement