Rough gallery plugin for Jekyll

gallery.rb

# Basic: add a `gallery` attribute to the YAML header of any page with value
# being the extension of your images. Every image with that extension stored
# inside the page's directory (and every one of its subdirectories) will be
# added to the `gallery_items` attribute of that same page (alphabetically
# sorted).

module Jekyll
  class Gallery < Generator
    safe true

    def generate site
      site.pages.each do |page|
        gallery(site, page) if page.data['gallery']
      end
    end

    def gallery site, page
      base = page.instance_variable_get :@dir
      search = File.join '**', "*.#{page.data['gallery']}"
      images = Dir.chdir(base[1..-1] || '.') do
        Dir.glob(search).sort.map {|image| File.join base, image}
      end
      page.data = page.data.deep_merge 'gallery_items' => images
    end
  end
end