def METHOD_NAME(self, tag):
    image_params = self.params.object_params(tag)
    image_chain = image_params.objects("image_backup_chain")
    self._source_nodes.append("drive_%s" % tag)
    self._full_bk_nodes.append("drive_%s" % image_chain[0])
    self._inc_bk_nodes.append("drive_%s" % image_chain[1])
    self._inc_bk_images.append(image_chain[1])
    self._snap_images.append(image_params["snap_image"])
    self._snap_nodes.append("drive_%s" % self._snap_images[-1])
    self._bitmaps.append("bitmap_%s" % tag)
    # Add the full backup image only before full backup
    self.params["image_backup_chain_%s" % tag] = image_chain[0]