Mine

	switch ($_FILES[$posted]["type"])
	{
		case "image/gif":
			return "gif";
			break;
		case "image/jpeg":
			return "jpg";
			break;
		case "image/pjpeg":
			return "jpg";
			break;
		case "image/x-png":
			return "png";
			break;
		case "image/png":
			return "png";
			break;
		case "application/x-gzip":
			return "tar.gz";
			break;
		case "application/gzip":
			return "tar.gz";
			break;
		case "application/x-tar":
			return "tar.gz";
			break;
		case "application/zip":
			return "zip";
			break;
		case "application/octet-stream":
			return "tar.bz2";
			break;
		default:
			return NULL;
			break;
	}