def image_transform(self, image_func, apply_to=None):
        """Modifies the images of a clip by replacing the frame `get_frame(t)` by
        another frame,  `image_func(get_frame(t))`.
        """
        apply_to = apply_to or []
        return self.transform(lambda get_frame, t: image_func(get_frame(t)), apply_to)
Modifies the images of a clip by replacing the frame `get_frame(t)` by
        another frame,  `image_func(get_frame(t))`.
        
moviepy/video/VideoClip.py