Optimize images using multiple utilities
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Optimize (lossless compress) images (jpeg, png, gif, svg) using external utilities:

Based on ImageOptim.app.

Gem Version Build Status Code Climate Dependency Status

Gem installation

gem install image_optim


Add to your Gemfile:

gem 'image_optim'

With version:

gem 'image_optim', '~> 0.11'

If you want to check latest changes:

gem 'image_optim', :git => 'git://github.com/toy/image_optim.git'

Binaries location

Simplest way for image_optim to locate binaries is to install them in common location present in PATH (see Binaries installation).

If you cannot install to common location, then install to custom one and add it to PATH.

Specify custom bin location using XXX_BIN environment variable (JPEGOPTIM_BIN, OPTIPNG_BIN, …).

Besides permanently setting environment variables in ~/.profile, ~/.bash_profile, ~/.bashrc, ~/.zshrc, … they can be set:

  • before command:

    PATH="/custom/location:$PATH" image_optim *.jpg

    for example:

    PATH="/Applications/ImageOptim.app/Contents/MacOS:$PATH" image_optim *.jpg

  • inside script:

    ENV['PATH'] = "/custom/location:#{ENV['PATH']}"; ImageOptim.optimize_images([…])

    for example:

    ENV['PATH'] = "/Applications/ImageOptim.app/Contents/MacOS:#{ENV['PATH']}"; ImageOptim.optimize_images([…])

Binaries installation

Linux - Debian/Ubuntu

sudo apt-get install -y advancecomp gifsicle jhead jpegoptim libjpeg-progs optipng pngcrush

Linux - RHEL/Fedora/Centos

sudo yum install -y advancecomp gifsicle jhead libjpeg optipng

You may also need to install libjpeg-turbo-utils instead of libjpeg:

sudo yum install -y libjpeg-turbo-utils

You will also need to install jpegoptim and pngcrush from source:


cd /tmp
curl -O http://www.kokkonen.net/tjko/src/jpegoptim-1.4.1.tar.gz
tar zxf jpegoptim-1.4.1.tar.gz
cd jpegoptim-1.4.1
./configure && make && make install


cd /tmp
curl -O http://iweb.dl.sourceforge.net/project/pmt/pngcrush/1.7.70/pngcrush-1.7.73.tar.gz
tar zxf pngcrush-1.7.73.tar.gz
cd pngcrush-1.7.73
make && cp -f pngcrush /usr/local/bin

OS X: Macports

sudo port install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush

OS X: Brew

brew install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush

pngout installation (optional)

You can install pngout by downloading and installing the binary versions.

Note: pngout is free to use even in commercial soft, but you can not redistribute, repackage or reuse it without consent and agreement of creator. license

svgo installation (optional)

svgo is available from NPM.

npm install -g svgo


From shell

image_optim *.{jpg,png,gif,svg}

image_optim -h

From ruby

Initialize optimizer (or you can call optimization methods directly on ImageOptim):

image_optim = ImageOptim.new

image_optim = ImageOptim.new(:pngout => false)

image_optim = ImageOptim.new(:nice => 20)

Optimize image getting temp path:


Optimize image in place:


Optimize image data:


Multiple images:

image_optim.optimize_images(Dir['*.png']) do |unoptimized, optimized|
  if optimized
    puts "#{unoptimized} => #{optimized}"



From rails

ImageOptim::Railtie will automatically register sprockets preprocessor unless you set config.assets.image_optim = false or config.assets.compress = false (later for partial rails 3 compatibility).

You can provide options for image_optim used for preprocessor through config config.assets.image_optim = {nice: 20, svgo: false} (ruby1.8 style: {:nice => 20, :svgo => false}). Check available options in options section.

Image optimization can be time consuming, so depending on your deployment process you may prefer to optimize original asset files.


Configuration in YAML format will be read and prepanded to options from two paths:

  • $XDG_CONFIG_HOME/image_optim.yml (by default ~/.config/image_optim.yml)
  • .image_optim.yml in current working directory

Example configuration:

nice: 20
pngout: false # disable
  level: 5


  • :nice — Nice level (defaults to 10)
  • :threads — Number of threads or disable (defaults to number of processors)
  • :verbose — Verbose output (defaults to false)

Worker can be disabled by passing false instead of options hash.

:pngcrush =>

  • :chunks — List of chunks to remove or :alla - all except tRNS/transparency or :allb - all except tRNS and gAMA/gamma (defaults to :alla)
  • :fix — Fix otherwise fatal conditions such as bad CRCs (defaults to false)
  • :brute — Brute force try all methods, very time-consuming and generally not worthwhile (defaults to false)

:pngout =>

  • :copy_chunks — Copy optional chunks (defaults to false)
  • :strategy — Strategy: 0 - xtreme, 1 - intense, 2 - longest Match, 3 - huffman Only, 4 - uncompressed (defaults to 0)

:optipng =>

  • :level — Optimization level preset: 0 is least, 7 is best (defaults to 6)
  • :interlace — Interlace, true - interlace on, false - interlace off, nil - as is in original image (defaults to false)

:advpng =>

  • :level — Compression level: 0 - don't compress, 1 - fast, 2 - normal, 3 - extra, 4 - extreme (defaults to 4)

:jhead =>

Worker has no options

:jpegoptim =>

  • :strip — List of extra markers to strip: :comments, :exif, :iptc, :icc or :all (defaults to :all)
  • :max_quality — Maximum image quality factor 0..100 (defaults to 100)

:jpegtran =>

  • :copy_chunks — Copy all chunks (defaults to false)
  • :progressive — Create progressive JPEG file (defaults to true)
  • :jpegrescan — Use jpegtran through jpegrescan, ignore progressive option (defaults to false)

:gifsicle =>

  • :interlace — Turn interlacing on (defaults to false)

:svgo =>

Worker has no options


Copyright (c) 2012-2014 Ivan Kuchin. See LICENSE.txt for details.