'Extract image disks from a compute node XML representation.
Extract image disk descriptions from a compute node XML representation,
converting the disks to an NodeImage object.
:type  compute: :class:`ElementTree`
:param compute: XML representation of a compute node.
:rtype:  :class:`NodeImage`.
:return: First disk attached to a compute node.'

def _extract_images(self, compute):

    disks = list()
    disk_list = compute.find('STORAGE')
    if (disk_list is not None):
        for element in disk_list.findall('DISK'):
            disks.append(NodeImage(id=element.attrib.get('image', None), name=None, driver=self.connection.driver, extra={'dev': element.attrib.get('dev', None)}))
    if (len(disks) > 0):
        return disks[0]
    else:
        return None
