image_optim

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

advpng from AdvanceCOMP (will use zopfli on default/maximum level 4)
gifsicle
jhead
jpegoptim
jpegtran from Independent JPEG Group's JPEG library
optipng
pngcrush
pngout
pngquant
svgo

Documentation for latest version and master.

Gem installation

gem install image_optim

Bundler

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 pngquant

If you get an old version of pngquant, please check how to install up-to-date version or compile from source at http://pngquant.org/.

Linux - RHEL/Fedora/Centos

sudo yum install -y advancecomp gifsicle jhead libjpeg optipng pngquant

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:

jpegoptim

Replace X.Y.Z with latest version number from http://www.kokkonen.net/tjko/projects.html#jpegoptim.

JPEGOPTIM_VERSION=X.Y.Z
cd /tmp
curl -O http://www.kokkonen.net/tjko/src/jpegoptim-$JPEGOPTIM_VERSION.tar.gz
tar zxf jpegoptim-$JPEGOPTIM_VERSION.tar.gz
cd jpegoptim-$JPEGOPTIM_VERSION
./configure && make && make install

pngcrush

Replace X.Y.Z with latest version number from http://sourceforge.net/projects/pmt/files/pngcrush/.

PNGCRUSH_VERSION=X.Y.Z
cd /tmp
curl -O http://iweb.dl.sourceforge.net/project/pmt/pngcrush/$PNGCRUSH_VERSION/pngcrush-$PNGCRUSH_VERSION.tar.gz
tar zxf pngcrush-$PNGCRUSH_VERSION.tar.gz
cd pngcrush-$PNGCRUSH_VERSION
make && cp -f pngcrush /usr/local/bin

OS X: Macports

sudo port install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush pngquant

OS X: Brew

brew install advancecomp gifsicle jhead jpegoptim jpeg optipng pngcrush pngquant

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

Usage

From shell

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

image_optim -r .

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:

image_optim.optimize_image('a.png')

Optimize image in place:

image_optim.optimize_image!('b.jpg')

Optimize image data:

image_optim.optimize_image_data(data)

Multiple images:

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

image_optim.optimize_images!(Dir['*.*'])

image_optim.optimize_images_data(datas)

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

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
optipng:
  level: 5

Options

: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.

:advpng =>

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

:gifsicle =>

:interlace — Turn interlacing on (defaults to false)

: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)

: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)

: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)

:pngquant =>

:quality — min..max - don't save below min, use less colors below max (both in range 0..100; in yaml - !ruby/range 0..100) (defaults to 100..100)
:speed — speed/quality trade-off: 1 - slow, 3 - default, 11 - fast & rough (defaults to 3)

:svgo =>