def set_web_presentation_properties(web_format, web_scale, web_crop):
    """Sets format, scaling and cropping information to create the
        web image.

        - ``web_format`` (str): either ``JPEG``, ``GIF`` or ``PNG``,

        - ``web_scale`` (str): WidthXHeight or nn.n%.

        - ``web_crop`` (str): X1xY1-X2xY2, crop-box or empty for no
          cropping.

        Raises ``ValueError`` if ``web_scale`` cannot be parsed.  If
        changing the settings succeed, it will update the web version
        of the image.
        """
