protected function removeThumbnails() {
		$thumbnail = $this->thumbnail;
		$smallthumb = $this->smallthumb;
		$largethumb = $this->largethumb;

		//delete standard thumbnail image
		if ($thumbnail) {
			$delfile = new ElggFile();
			$delfile->owner_guid = $this->getOwnerGUID();
			$delfile->setFilename($thumbnail);
			$delfile->delete();
		}
		//delete small thumbnail image
		if ($smallthumb) {
			$delfile = new ElggFile();
			$delfile->owner_guid = $this->getOwnerGUID();
			$delfile->setFilename($smallthumb);
			$delfile->delete();
		}
		//delete large thumbnail image
		if ($largethumb) {
			$delfile = new ElggFile();
			$delfile->owner_guid = $this->getOwnerGUID();
			$delfile->setFilename($largethumb);
			$delfile->delete();
		}
	}