我正在使用以下代码向wordpress中的rss提要添加一个特色图像。

add_action( \'rss2_item\', \'add_post_featured_image_as_rss_item_enclosure\' );

function add_post_featured_image_as_rss_item_enclosure() {
if ( ! has_post_thumbnail() )
    return;

$thumbnail_size = apply_filters( \'rss_enclosure_image_size\', \'thumbnail\' );
$thumbnail_id = get_post_thumbnail_id( get_the_ID() );
$thumbnail = image_get_intermediate_size( $thumbnail_id, $thumbnail_size );

if ( empty( $thumbnail ) )
    return;

$upload_dir = wp_upload_dir();

 printf( 
    \'<enclosure url="%s" length="%s" type="%s" />\',
    $thumbnail[\'url\'], 
    filesize( path_join( $upload_dir[\'basedir\'], $thumbnail[\'path\'] ) ), 
    get_post_mime_type( $thumbnail_id ) 
 );
}

但上面的plguin输出的图像非常小，为150x150。我尝试将缩略图大小更改为“全”或“大”，但它不起作用。有没有办法在下面的附件字段中为全功能图像大小添加url？

提前感谢

$thumb_id = get_post_thumbnail_id(get_the_ID());    
$thumb_data = wp_get_attachment_image_src( $thumb_id, \'full\');