how to post image to Restful Wcf Service in silverlight

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WCF

Silverlight

REST

WCFServices

Hi ,
I have a Wcf Service who has method to store image passed at configurable path.

Here is my WCf Service interface :

[ServiceContract]
public interface IFileUploader
{
   [OperationContract]
   [WebInvoke(Method = "POST", UriTemplate = "FileUpload/{fileName}", ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
       void SaveFile(string fileName, Stream file);
}

i have implemented it , using some custome class lib.

At Client side :

i tried using Web Client but has not came cross image/file uploading.
and used HttpWebClient as well here is the code :

public void SomeMethod()
{
   HttpWebRequest uploadReq = (HttpWebRequest)WebRequest.Create(fileUploadSvcBaseUri + "/FileUpload");
   uploadReq.Method = "POST";
   uploadReq.ContentType = "image/png";
   //var bytearr = new byte[fileStream.ReadByte(]
                
   uploadReq.BeginGetRequestStream(new AsyncCallback(getStreamCallBack), uploadReq);
   fileStreamForUpload.Add(dialpg.File);
}

public void getStreamCallBack(IAsyncResult asynchronousResult)
{
   try
   {
      HttpWebRequest request = (HttpWebRequest)asynchronousResult.AsyncState;
      HttpWebResponse response = (HttpWebResponse)request.EndGetResponse(asynchronousResult);
      using (StreamWriter streamWriter = new StreamWriter(response.GetResponseStream()))
      {
         //string resultString = streamReader1.ReadToEnd();
         //strea
         //resultBlock.Text = "Using HttpWebRequest: " + resultString;
         var fileByteArray = File.ReadAllText(fileStreamForUpload[0].DirectoryName).ToCharArray();
         streamWriter.Write(fileByteArray, 0, fileByteArray.Length);
         streamWriter.Close();
      }
      //using (StreamWriter wrtr = new StreamWriter(request.))
   }
   catch (Exception)
   {
      throw;
   }
}

fileStreamForUpload is a list of FileInfo.
Error in call back [getStreamCallBack] :

System.ArgumentException: Value does not fall within the expected range.