public static void sendMultiPartReq(Stream req, string boundaryString, object[] files, object[] parameters)
        {
            byte[] b;
            foreach (string[] file in files)
            {
                b = Encoding.UTF8.GetBytes(
                    "\r\n" + boundaryString + "\r\n" +
                    String.Format("Content-Disposition: form-data; name=\"{0}\"; filename=\"{1}\"\r\n", file[0], Path.GetFileName(file[1])) +
                    "Content-Type: image/png\r\n\r\n");
                req.Write(b, 0, b.Length);
                if (File.Exists(file[1]))
                {
                    b = File.ReadAllBytes(file[1]);
                    req.Write(b, 0, b.Length);
                }
                b = Encoding.UTF8.GetBytes("\r\n");
                req.Write(b, 0, b.Length);
            }
            foreach (string[] parameter in parameters)
            {
                b = Encoding.UTF8.GetBytes(
                    boundaryString + "\r\n" +
                    String.Format("Content-Disposition: form-data; name=\"{0}\"\"\r\n", parameter[0]) +
                    "Content-Type: image/png\r\n\r\n" +
                    parameter[1] +
                    "\r\n");
                req.Write(b, 0, b.Length);
            }
            b = Encoding.UTF8.GetBytes(boundaryString);
            req.Write(b, 0, b.Length);
        }