Picasa Web Album Data API v2:(400)错误请求'上传带有元数据的照片时抛出错误

我正在尝试使用Picasa Web Album Data API v2在c#中上传带有元数据的图像，正如这里的文档中提到的。

http post请求失败，400错误请求错误，没有详细说明我的请求缺失或哪里是畸形的

下面是我的代码:

      byte[] image = System.IO.File.ReadAllBytes("fullimagepath");
            int imglenth= image.Length;
            string text = Encoding.ASCII.GetString(image);
            string rawImgXml="<entry xmlns=''http://www.w3.org/2005/Atom''>"+"'n"+
                "<title>plz-to-love-realcat.png</title>"+"'n"+
                "<summary>Real cat wants attention too</summary>"+"'n"+
                "<category scheme='"http://schemas.google.com/g/2005#kind'"'n"+
                "term='"http://schemas.google.com/photos/2007#photo'"/>"+"'n"+
                "</entry>";
            string data = "";
             data ="'nMedia multipart posting'n"+
                "--END_OF_PART'n"+
                      "Content-Type: application/atom+xml'n'n"+
                        rawImgXml + "'n"
                +"--END_OF_PART'n"
                +"Content-Type: image/png'n"+
                           text+"'n"+
                "--END_OF_PART--";
            int length=data.Length;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://picasaweb.google.com/data/feed/api/user/"+tc.userId+"/albumid/"+"6150508893827643953"+"?access_token="+tc.auth_Token);
            byte[] bytes;
            bytes = System.Text.Encoding.ASCII.GetBytes(data);
            request.ContentType = "multipart/related; boundary=END_OF_PART";
            request.ContentLength = length;
            request.Headers.Add("GData-Version","2");
            request.Headers.Add("MIME-Version","1.0");
            request.Method = "POST";
            Stream requestStream = request.GetRequestStream();
            int start = 0;
            int chunkSize = 1024 * 4; // changed form 100 to 4
            double percentage = 0;
            while (start <= bytes.Length)
            {
                if (start + chunkSize > bytes.Length)
                    requestStream.Write(bytes, start, bytes.Length - start);
                else
                    requestStream.Write(bytes, start, chunkSize);
                start += chunkSize;
            }
            HttpWebResponse response;
            response = (HttpWebResponse)request.GetResponse();
            Stream responseStream = response.GetResponseStream();
            string responseStr = new StreamReader(responseStream).ReadToEnd();

图像数据正在被转换为ASCII，然后附加到数据字符串。在尝试了过去3天的许多排列和组合后，它失败了，同样的错误。完全不知道请求哪里出了问题?

上传没有元数据的图像工作完美，但我想在我的应用程序中也上传视频，这不能没有元数据。

任何指示或指针将大有帮助!提前非常感谢!