def _parse_tree(self, node):
        """ Parse a <image> object """
        if 'type' in node.attrib:
            self.kind = node.attrib['type']
        if 'width' in node.attrib:
            self.width = int(node.attrib['width'])
        if 'height' in node.attrib:
            self.height = int(node.attrib['height'])
        self.url = node.text