include image tag for jekyll(Octopress)

include_img.rb

# Title: Include Image Tag for Jekyll
# Authors: choplin
# Description: Include <img> tag with src from a specified directory
# Configuration: as below in your _config.yml (images/blog as default)
#
# image_dir: images/blog
#
# Syntax {% include_img [class name(s)] image_file.(jpg|jpeg|png|gif) [width [height]] [title text | "title text" ["alt text"]] %}
#
# Examples:
# {% include_img test.jpg %}
#
# Output:
# <img src="/images/blog/test.jpg">
#
module Jekyll

  class IncludeImageTag < Liquid::Tag
    @img = nil

    def initialize(tag_name, markup, tokens)
      attributes = ['class', 'src', 'width', 'height', 'title']

      if markup =~ /^(?<class>\S.*\s+)?(?<src>\S+\.(?:jpg|jpeg|png|gif))(?:\s+(?<width>\d+))?(?:\s+(?<height>\d+))?(?:\s+(?<title>.+))?/i
        @img = attributes.reduce({}) { |img, attr| img[attr] = $~[attr].strip if $~[attr]; img }
        if /(?:"|')(?<title>[^"']+)?(?:"|')\s+(?:"|')(?<alt>[^"']+)?(?:"|')/ =~ @img['title']
          @img['title']  = title
          @img['alt']    = alt
        else
          @img['alt']    = @img['title'].gsub!(/"/, '&#34;') if @img['title']
        end
        @img['class'].gsub!(/"/, '') if @img['class']
      end
      super
    end

    def render(context)
      if @img
        image_dir = (context.registers[:site].config['image_dir'].sub(/^\//,'') || 'images/blog')
        @img['src'] = "/#{image_dir}/#{@img['src']}"
        "<img #{@img.collect {|k,v| "#{k}=\"#{v}\"" if v}.join(" ")}>"
      else
        "Error processing input, expected syntax: {% include_img [class name(s)] [http[s]:/]/path/to/image [width [height]] [title text | \"title text\" [\"alt text\"]] %}"
      end
    end
  end
end

Liquid::Template.register_tag('include_img', Jekyll::IncludeImageTag)

Yay Ruby!!