public function addCover($src, $dest = '', $id = 'cover'){
		if( file_exists($src) ){
			if( !$dest ){
				$dest = 'Image'.DIRECTORY_SEPARATOR.basename($src);
			}
			$this->distributor->copy($src, 'OEBPS'.DIRECTORY_SEPARATOR.$dest);
			$this->opf->addItem($dest, $id, ['cover-image']);
			$this->opf->addMeta('meta', '', [
				'name' => 'cover',
				'content' => $id
			]);
		}
	}