guetzli

JPEG encoder that optimizes for visual quality at small file sizes

TLDR

Compress JPEG

$ guetzli [input.jpg] [output.jpg]

Set quality level

$ guetzli --quality [90] [input.jpg] [output.jpg]

Compress PNG to JPEG

$ guetzli [input.png] [output.jpg]

Maximum compression

$ guetzli --quality [84] [input.jpg] [output.jpg]

SYNOPSIS

guetzli [options] input output

Guetzli is a JPEG encoder that optimizes for visual quality at small file sizes. It uses a perceptual model to achieve 20-30% smaller files than libjpeg.
The tool is computationally intensive, trading encoding time for better compression. It maintains visual quality while reducing file size significantly.

PARAMETERS

INPUT

Input image (JPEG or PNG).

OUTPUT

Output JPEG file.

--quality N

Quality (84-100, default 95).

--memlimit N

Memory limit in MB.

--verbose

Verbose output.

--help

Display help information.

CAVEATS

Very slow encoding. High memory usage. Quality below 84 not recommended.

HISTORY

Guetzli was developed by Google and released in 2017 as a perceptually-guided JPEG encoder.