let xml_of_image i =
Element ("image", [],
[ Element("url",[],[PCData i.image_url]) ;
Element("title",[],[PCData i.image_title]) ;
Element("link",[],[PCData i.image_link])
] @
(List.flatten
[ opt_element
(apply_opt string_of_int i.image_width)
"width";
opt_element
(apply_opt string_of_int i.image_height)
"height";
opt_element i.image_desc "description" ;
]
)
)