    # File lib/rubygame/mediabag.rb, line 83
        def load_file(filename)
          case File::extname(filename).downcase[1..-1]
          when *(@@image_ext)
            return load_image(filename)
          when *(@@sound_ext)
            return load_sound(filename)
          else
            raise(ArgumentError,"Unrecognized file extension `%s': %s"%
                  [File::extname(filename), filename])
          end
        end