Return |Exif| instance having header properties parsed from Exif
        image in *stream*.

def from_stream(cls, stream):
        """
        Return |Exif| instance having header properties parsed from Exif
        image in *stream*.
        """
        markers = _JfifMarkers.from_stream(stream)
        # print('\n%s' % markers)

        px_width = markers.sof.px_width
        px_height = markers.sof.px_height
        horz_dpi = markers.app1.horz_dpi
        vert_dpi = markers.app1.vert_dpi

        return cls(px_width, px_height, horz_dpi, vert_dpi)