Middleman Images Extension

Resize and optimize your images on the fly with Middleman. Just run middleman build and all your images will get the minimizing treatment. Middleman Images currently depends on mini_magick for resizing and image_optim for optimizing your images.

We deactivated the travis.com CI pipeline as we moved all repositories to Github Actions. As this package is not in active development right now, we do not plan to migrate this repository to Github Actions. If you want to continue developing on this Gem you can migrate the steps from the .travis.yml to a new workflow file for Github Actions relatively easily.

gem 'middleman-images'

# For resizing images:
gem 'mini_magick'

# For optimizing images:
gem 'image_optim'

Resizing images requires the gem mini_magick and ImageMagick binaries to be available. Check mini_magick for more information.

Optimizing images require the gem image_optim. Check image_optim for more information.

ImageOptim uses different tools to optimize image files. The easiest way to make sure, most of these tools are available, is by including them via a seperate gem:

gem 'image_optim_pack'

For more information check image_optim_pack

To activate the extension just put this into your config.rb:

activate :images

With Middleman images activated, starting the Middleman server will take some time. During that time images that need procssing will get registered. The actual processing of the images takes place while navigating the page.

Configure the extension by passing a block to :activate:

activate :images do |images|
  # Do not include original images in the build (default: false)
  images.ignore_original = true

  # Specify another cache directory depending on your root directory (default: 'cache')
  images.cache_dir = 'funky_cache/subdir_of_funky_cache'

  # Optimize images (default: false)
  images.optimize = true

  # Provide additional options for image_optim
  # See https://github.com/toy/image_optim for all available options
  images.image_optim = {
    nice: 20,
    optipng: {
      level: 5,
    },
  }
end

By default Middleman Images won't do anything to your images.

Middleman images supports a wide variety of options. You can look up all actions in the ImageMagick documentation.

To resize your images, set the option resize on the middleman helpers image_tag or image_path.

<%= image_tag 'example.jpg', resize: '200x300' %>

becomes:

<img src="/assets/images/example-200x300-opt.jpg" alt="Example" />

The image example.jpg will be resized, optimized and saved to example-200x300-opt.jpg.

We use ImageMagick for resizing, which respects the aspect ratio of your images when resizing. You can make ImageMagick ignore the aspect ratio by appending ! to resize.

<%= image_tag 'example.jpg', resize: '200x300!' %>

Since Middleman Images just passes the resize string to ImageMagick, you can use all options available. Check the ImageMagick documentation for resize for all available options.

To crop your images, set the option crop on the middleman helpers image_tag or image_path.

<%= image_path 'example.jpg', crop: '200x300' %>

You can enable (or disable) optimization for some images by providing the optimize option.

<%= image_path 'example.jpg', resize: '200x300', optimize: false %>

becomes:

/assets/images/example-200x300.jpg

Using srcset with Middleman Images is possible via the image_path helper. This is how Middleman handles srcsets in conjunction with the :asset_hash option (see Middleman#File Size Optimization).

<img src="<%= image_path 'example.jpg', resize: '200x300' %>"
     srcset="<%= image_path 'example.jpg', resize: '400x600' %> 2x" />

Middleman Images will create a cache Folder in your app directory (or the folder name you specified as cache_dir). It will save the processed images in there. This is necessary to work with other plugins like asset_hash and to make sure unchanged images are not reprocessed on rebuild. Deleting this directory is not critical, but it will force Middleman Images to rebuild all images on the next build, so you should do this with care.