protected function deleteResamplings() {
        $children = ContentServiceAsset::get()->filter('SourceID', $this->ID);

        $numDeleted = 0;
        foreach ($children as $child) {
            $child->SourceID = -1;

            // we _DONT_ do a hard delete; if content has this image cached, it should be able to
            // hold it for a while. Instead, mark deleted and allow a cleanup job to collect it later
            $child->Filename = 'deleted';
            $child->write();
            $numDeleted++;
        }

        $this->Resamplings = array();
        return $numDeleted;
    }