    int JpegImage::writeHeader(BasicIo& outIo) const
    {
        // Jpeg header
        byte tmpBuf[2];
        tmpBuf[0] = 0xff;
        tmpBuf[1] = soi_;
        if (outIo.write(tmpBuf, 2) != 2) return 4;
        if (outIo.error()) return 4;
        return 0;
    }
Unknown