Return a new |ImagePart| instance containing *image*, which is an
        |Image| object.

def new(cls, package, image):
        """
        Return a new |ImagePart| instance containing *image*, which is an
        |Image| object.
        """
        partname = package.next_image_partname(image.ext)
        return cls(
            partname, image.content_type, image.blob, package, image.filename
        )