middleman/middleman-core/lib/middleman-more/extensions/automatic_alt_tags.rb

# Automatic Image alt tags from image names extension
class Middleman::Extensions::AutomaticAltTags < ::Middleman::Extension
  helpers do
    # Override default image_tag helper to automatically insert alt tag
    # containing image name.

    def image_tag(path, params={})
      unless path.include?('://')
        params[:alt] ||= ''

        real_path = path
        real_path = File.join(images_dir, real_path) unless real_path.start_with?('/')
        full_path = File.join(source_dir, real_path)

        if File.exist?(full_path)
          begin
            alt_text = File.basename(full_path, '.*')
            alt_text.capitalize!
            params[:alt] = alt_text
          end
        end
      end

      super(path, params)
    end
  end
end