问如何使用Graph API更新头像封面照片？

EN

$args = array('name' => 'awesome album name', 'message' => 'awesome album message');
try {
    $album_id =$facebook->api("/$page_id/albums", 'post', $args);
}catch(Exception $e){
    echo $e->getMessage();
}

$args = array('image' =>'@'.realpath('/var/www/facebook.png'));
try{
    $uploaded_photo_details = $facebook->api("/{$album_id['id']}/photos", 'post', $args);
}catch(Exception $e){
    echo $e->getMessage();
}

if(isset($uploaded_photo_details['id'])){
$args = array('cover' => $uploaded_photo_details['id'], 'offset_y' =>0);
try {
    $cover_details = $facebook->api("/{$page_id}", 'post', $args);
}catch(Exception $e){
    echo $e->getMessage();
}