image_optim

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

• advpng from AdvanceCOMP
• gifsicle
• jhead
• jpegoptim
• jpegtran from Independent JPEG Group's JPEG library
• optipng
• pngcrush
• pngout

Based on ImageOptim.app.

Gem installation

gem install image_optim

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 will also need to install jpegoptim and pngcrush from source:

jpegoptim

cd /tmp
curl -O http://www.kokkonen.net/tjko/src/jpegoptim-1.3.0.tar.gz
tar zxf jpegoptim-1.3.0.tar.gz
cd jpegoptim-1.3.0
./configure && make && make install

pngcrush

cd /tmp
curl -O http://iweb.dl.sourceforge.net/project/pmt/pngcrush/1.7.70/pngcrush-1.7.70.tar.gz
tar zxf pngcrush-1.7.70.tar.gz
cd pngcrush-1.7.70
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

Usage

From shell

image_optim *.{jpg,png,gif}

image_optim -h

From ruby

Initilize optimizer:

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 initialize processing of assets if config.assets.compress is true.

As image optimization can be time consuming you may prefer to optimize original asset files.

Automatic assets processing can be turned off by setting config.assets.image_optim = false.

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.

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)

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)

Copyright

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