docs: def default_cx(self):
          """
          Native width of this image, calculated from its width in pixels and
          horizontal dots per inch (dpi).
          """
          px_width = self.image.px_width
          horz_dpi = self.image.horz_dpi
          width_in_inches = px_width / horz_dpi
          return Inches(width_in_inches)