public static function to_webp(string $from, $to=null, $cwebp=null, $gif2webp=null, bool $refresh=false) {
		// Try binaries first, fallback to GD.
		return (
			static::to_webp_binary($from, $to, $cwebp, $gif2webp, $refresh) ||
			static::to_webp_gd($from, $to, $refresh)
		);
	}