vocalfan/millipng

Very thorough (and slow) png optimizer

millipng

Very slow png optimizer

• Overview
  • Features
• Usage
  • Recommendation
• License

Overview

millipng is a .png meta-optimizer.

A meta-optimizer? millipng is not an optimizer by itself, it just calls multiple existing optimizers (deflopt, defluff, optipng, pngoptimizer, pngout, truepng, zopflipng) in a specific order described by (not mine) analysis here: reddit.com/r/webdev/wiki.

millipng is a lossless png optimizer (except removing exif and alpha channel color info).

millipng is distributed as a docker image. This ensures consistent runtime environment with no configuration on your side (few of the included optimizers require wine to run on non Windows OS, which is already setup in the image).

Features

• ✨ Best in class optimization
• 📂 Optimize single file or whole directory

Usage

# optimize all pngs in current directory (recursively)
docker run -v "$PWD:/img" matejkosiarcik/millipng

# optimize single png
docker run -v "$PWD/image.png:/img" matejkosiarcik/millipng

When in doubt, get help:

$ docker run matejkosiarcik/millipng --help
usage: millipng [-h] [-V] [-l {fast,default,brute,ultra-brute}] [-n] [-j JOBS]
                [-v | -q]

optional arguments:
  -h, --help            show this help message and exit
  -V, --version         show program's version number and exit
  -l {fast,default,brute,ultra-brute}, --level {fast,default,brute,ultra-brute}
                        Optimization level
  -n, --dry-run         Do not actually modify images
  -j JOBS, --jobs JOBS  Number of parallel jobs/threads to run (default is 0 -
                        automatically determine according to current cpu)
  -v, --verbose         Additional logging output
  -q, --quiet           Suppress default logging output

Recommendation

For maximum optimization, I recommend

1. call pngquant before millipng (beware pngquant is lossy)
2. use --level ultra-brute in millipng (beware this takes a really long time for any sizible png)

Example:

pngquant --strip --speed 1 --skip-if-larger --quality 0-95 --force 'image.png' --output 'image.png'
docker run -v "$PWD/image.png:/img" matejkosiarcik/millipng --level ultra-brute

License

The project is licensed under LGPLv3. See LICENSE.txt for full details.