how to append to an xml file with XDocument and XElement

            XDocument xDoc = XDocument.Load(_filePath);
            XElement root = xDoc.Root;

            root.Add(new XElement("MenuItem",
                new XElement("Name", "ttttt"),
                new XElement("Url", "www.this.com"),
                new XElement("Images",
                    new XElement("image", "img1"),
                    new XElement("image", "img2")
                    )
                )
            );

            root.Save(_filePath);


<?xml version="1.0" encoding="utf-8"?>
<MenuItems>
  <MenuItem>
    <Name>rrrrrr</Name>
    <Url>www.this1.com</Url>
    <Images>
    <image>img1</image>
    <image>img2</image>
    </Images>
  </MenuItem>
  <MenuItem>
    <Name>ttttt</Name>
    <Url>www.this.com</Url>
    <Images>
      <image>img1</image>
      <image>img2</image>
    </Images>
  </MenuItem>
</MenuItems>