i dont know php so is hard 🙂
replace
// do something special for gallery fields
with
<?php
$image_ids = get_field('gallery', false, false);
$shortcode = '[' . 'gallery ids="' . implode(',', $image_ids) . '"]';
echo do_shortcode( $shortcode );
?>
or
$image_ids = get_field('gallery', false, false);
$shortcode = '[' . 'gallery ids="' . implode(',', $image_ids) . '"]';
echo do_shortcode( $shortcode );
in this code do I have to replace something?