code: func NewScreenFramebufferImage(width, height int) *Image {
  	i := &Image{
  		image:  graphicscommand.NewScreenFramebufferImage(width, height),
  		screen: true,
  	}
  	i.clear()
  	theImages.add(i)
  	return i
  }
docs: // NewScreenFramebufferImage creates a special image that framebuffer is one for the screen.
  //
  // The returned image is cleared.
  //
  // Note that Dispose is not called automatically.