Well Broke, to Drive Double, Traffic Safe, Sound

// Outputs hidden anchors for all image attachments on the current Horse post,
// so Elementor's lightbox can show them as one slideshow group.
add_shortcode('horse_gallery_lightbox', function () {
if ( ! is_singular() ) return '';
$post_id = get_the_ID();
$attachments = get_posts([
'post_type' => 'attachment',
'post_mime_type' => 'image',
'posts_per_page' => -1,
'post_parent' => $post_id,
'orderby' => 'menu_order',
'order' => 'ASC',
'fields' => 'ids',
]);
if ( ! $attachments ) return '';
$out = '<div class="horse-lightbox-hidden" style="display:none">';
foreach ( $attachments as $att_id ) {
$url = wp_get_attachment_image_url( $att_id, 'full' );
if ( $url ) {
$out .= '<a href="' . esc_url( $url ) . lementor-open-lightbox="yes" data-elementor-lightbox-slideshow="horse-gallery"></a>';
}
}
$out .= '</div>';
return $out;
});