public static function placeholder_to_course_image($show, $post_id)
{
$course_id = !empty($post_id) ? get_post_meta($post_id, 'course_id', true) : 0;
if (!empty($course_id)) {
self::$course_id = $course_id;
add_filter('mp_default_product_img', array(__CLASS__, 'replace_image'));
return 1;
}
return $show;
}
