一見、意味を測りかねる、remove_filter()、関数内の、add_filter() ちゃんと意味があるんですね。
function filter_gallery_shortcode_output_29832( $gallery, $attr ) {
remove_filter( 'post_gallery', __FUNCTION__, 10, 2 );
$gallery= gallery_shortcode( $attr );
add_filter( 'post_gallery', __FUNCTION__, 10, 2 );
// Change the output
// $gallery= ...
return $gallery;
}
add_filter( 'post_gallery', 'filter_gallery_shortcode_output_29832', 10, 2 );