Reply To: Convert Attachments to Gallery

• John Huebner

• October 3, 2016 at 7:18 am

You could create an acf/load_field filter https://www.advancedcustomfields.com/resources/acfload_field/ or an acf/load_value filter https://www.advancedcustomfields.com/resources/acfload_value/. You could then use the WP get_attached_media() function https://codex.wordpress.org/Function_Reference/get_attached_media to get all of the media for a post.

add_filter('acf/load_value/name=your-field-name', 'build_gallery_from_attachments', 10, 3);
function build_gallery_from_attachments($value, $post_id, $field) {
  if (!empty($value)) {
    // already has a value
    return;
  }
  // does not have a value, build value from attachments
  $media = get_attached_media('image', $post_id);
  $value = array();
  if ($media) {
    foreach ($media as $image) {
      $value[] = $image->ID;
    }
  }
  return $value;
}