def image(name, identifier={:index => 0}, &block)
      standard_methods(name, identifier, 'image_for', &block)
      define_method("#{name}_loaded?") do
        return platform.image_loaded_for identifier.clone unless block_given?
        self.send("#{name}_element").loaded?
      end
    end
def image(name, identifier={:index => 0}, &block)
      standard_methods(name, identifier, 'image_for', &block)
      define_method("#{name}_loaded?") do
        return platform.image_loaded_for identifier.clone unless block_given?
        self.send("#{name}_element").loaded?
      end
    end
adds three methods - one to retrieve the image element, another to
 check the load status of the image, and another to check the
 image's existence.

 @example
   image(:logo, :id => 'logo')
   # will generate 'logo_element', 'logo_loaded?', and 'logo?' methods

 @param [Symbol] the name used for the generated methods
 @param [Hash] identifier how we find an image.
 @param optional block to be invoked when element method is called