# File lib/action_view/helpers/asset_tag_helper.rb, line 155
      def image_path(source)
        unless (source.split("/").last || source).include?(".") || source.blank?
          ActiveSupport::Deprecation.warn(
            "You've called image_path with a source that doesn't include an extension. " +
            "In Rails 2.0, that will not result in .png automatically being appended. " +
            "So you should call image_path('#{source}.png') instead", caller
          )
        end

        compute_public_path(source, 'images', 'png')
      end