'Return an |InlineShape| instance containing the image identified by
*image_path_or_stream*, added to the end of this run.
*image_path_or_stream* can be a path (a string) or a file-like object
containing a binary image. If neither width nor height is specified,
the picture appears at its native size. If only one is specified, it
is used to compute a scaling factor that is then applied to the
unspecified dimension, preserving the aspect ratio of the image. The
native size of the picture is calculated using the dots-per-inch
(dpi) value specified in the image file, defaulting to 72 dpi if no
value is specified, as is often the case.'

def add_picture(self, image_path_or_stream, width=None, height=None):

    inline = self.part.new_pic_inline(image_path_or_stream, width, height)
    self._r.add_drawing(inline)
    return InlineShape(inline)
