Minify PNG, JPEG and GIF images

npm install grunt-contrib-imagemin
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grunt-contrib-imagemin v0.6.0 Build Status

Minify PNG, JPEG and GIF images

Getting Started

This plugin requires Grunt ^0.4.0

If you haven't used Grunt before, be sure to check out the Getting Started guide, as it explains how to create a Gruntfile as well as install and use Grunt plugins. Once you're familiar with that process, you may install this plugin with this command:

npm install grunt-contrib-imagemin --save-dev

Once the plugin has been installed, it may be enabled inside your Gruntfile with this line of JavaScript:


Imagemin task

Run this task with the grunt imagemin command.

Task targets, files and options may be specified according to the grunt Configuring tasks guide.

Minify images using OptiPNG, pngquant, jpegtran and gifsicle.

We recommend using grunt-newer to only process changed files as minifying images can be quite slow.


Options will only apply to the relevant files, so you don't need separate targets for png/jpg.

optimizationLevel (png only)

Type: Number Default: 7

Select optimization level between 0 and 7.

The optimization level 0 enables a set of optimization operations that require minimal effort. There will be no changes to image attributes like bit depth or color type, and no recompression of existing IDAT datastreams. The optimization level 1 enables a single IDAT compression trial. The trial chosen is what. OptiPNG thinks it’s probably the most effective. The optimization levels 2 and higher enable multiple IDAT compression trials; the higher the level, the more trials.

Level and trials:

  1. 1 trial
  2. 8 trials
  3. 16 trials
  4. 24 trials
  5. 48 trials
  6. 120 trials
  7. 240 trials

progressive (jpg only)

Type: Boolean Default: true

Lossless conversion to progressive.

interlaced (gif only)

Type: Boolean Default: true

Interlace gif for progressive rendering.


Type: Boolean Default: false

Whether to enable pngquant compression.

pngquant is a command-line utility for converting 24/32-bit PNG images to paletted (8-bit) PNGs. The conversion reduces file sizes significantly (often as much as 70%) and preserves full alpha transparency.

Example config

You can either map your files statically or dynamically.

  imagemin: {                          // Task
    static: {                          // Target
      options: {                       // Target options
        optimizationLevel: 3
      files: {                         // Dictionary of files
        'dist/img.png': 'src/img.png', // 'destination': 'source'
        'dist/img.jpg': 'src/img.jpg',
        'dist/img.gif': 'src/img.gif'
    dynamic: {                         // Another target
      files: [{
        expand: true,                  // Enable dynamic expansion
        cwd: 'src/',                   // Src matches are relative to this path
        src: ['**/*.{png,jpg,gif}'],   // Actual patterns to match
        dest: 'dist/'                  // Destination path prefix

grunt.registerTask('default', ['imagemin']);

Release History

  • 2014-03-28   v0.6.0   Updated "image-min" to 0.2 Added percentage to size saved view - fixes cache option removed. Adds "pretty-bytes".
  • 2014-01-13   v0.5.0   Extract the logic into an external lib image-min.
  • 2014-01-08   v0.4.1   Prevent "Maximum call stack size exceeded". Speed up loading this task by lazy requiring bin deps.
  • 2013-11-22   v0.4.0   The pngquant option is now false by default instead of true.
  • 2013-09-09   v0.3.0   Add interlace option for gif files.
  • 2013-08-16   v0.2.0   Add gifsicle and pngquant. Cache images so only changed images are optimized. Default optimizationLevel to 7 and progressive to true.
  • 2013-04-10   v0.1.4   Fix exception when running in verbose mode.
  • 2013-04-05   v0.1.3   Fix OptiPNG not being able to overwrite file. Allow overwriting src when dest/src is the same. Limit to 10 concurrent optimizations.
  • 2013-02-22   v0.1.2   Fix OptiPNG not working on some systems. Prevent OptiPNG from producing .bak files.
  • 2013-02-15   v0.1.1   First official release for Grunt 0.4.0.
  • 2013-01-30   v0.1.1rc8   Fix task not creating destination folders
  • 2013-01-30   v0.1.1rc7   Updating to work with grunt v0.4.0rc7. Switching to this.files api.
  • 2012-11-01   v0.1.0   Initial release.

Task submitted by Sindre Sorhus

This file was generated on Fri Mar 28 2014 19:43:56.

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