middleman-imgix 
middleman-imgix is an extension for the Middleman static site generator that allows you to run all of your images (or only some) through imgix for all sorts of fun features.
Installation
From inside the Gemfile of your Middleman project | add:
gem 'middleman-imgix'
Then run bundle install
Configuration
Activate the extension in your config.rb file, and supply your required imgix host:
activate :imgix, host: 'your-subdomain.imgix.net'
A number of other options are supported as well (see the imgix gem for more info):
activate :imgix, host: 'your-subdomain.imgix.net', secure_url_token: 'your-token', shard_strategy: :cycle
Here's a list of all available options:
| Option | Default | Description |
|---|---|---|
host (required) |
nil |
A string or array of your imgix hosts. |
secure_url_token |
nil |
Your imgix secure_url_token. |
use_https |
true |
Whether to use http or https for imgix. |
shard_strategy |
:crc |
Your imgix shard strategy. |
include_library_param |
true |
Include the imgix library param in each URL. |
default_params |
{ auto: 'format' } |
Default imgix params to use on all images. |
imgix_js_version |
nil |
Converts image_tags to support imgix.js version 2 or 3. |
exts |
%w(.png .jpg .jpeg) |
List of file extensions that get converted to imgix URLs. |
sources |
%w(.css .htm .html .js .php .xhtml) |
List of source extensions that are searched for imgix images. |
ignore |
[] |
Regexes of filenames to skip adding imgix to. |
rewrite_ignore |
[] |
Regexes of filenames to skip processing for path rewrites. |
Usage
After activating the extension, all applicable image URLs throughout your site (HTML, CSS, etc.) will begin pointing to imgix. For example...
image_tag 'example.png'
#=> <img src="https://your-subdomain.imgix.net/images/example.png?ixlib=rb-1.1.0&auto=format" />
imgix.js
If you're using imgix.js for responsive images (you still need to include that JS file yourself), you can configure the imgix_js_version option to have the output from image_tag generate specific markup for your imgix.js version.
imgix_js_version: 3
image_tag 'example.png'
#=> <img ix-src="https://your-subdomain.imgix.net/images/example.png?ixlib=rb-1.1.0&auto=format" />
imgix_js_version: 2
image_tag 'example.png'
#=> <img data-src="https://your-subdomain.imgix.net/images/example.png?ixlib=rb-1.1.0&auto=format" class="imgix-fluid" />