query attachment images … if no attachments -> get attachments of parent page?

You can use get_children to check if it returns anything, then if it doesn’t, fetch the parent attachments.

//loop stuff

//your $query_images_args

$attachments = get_children($query_images_args);

if ( empty($attachments) ) {

//go get parent attachments 

}else{

//loop through this post's attachments

}