send mail with image attachment

public  void button3_Click(object sender, EventArgs e)
{
    MailMessage message = new MailMessage(
       "from@gmail.com",
       "to@hotmail.com",
       "Quarterly data report.",
       "See the attached spreadsheet.");

    MemoryStream stream = new MemoryStream();
    realimage[0].Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
   // MemoryStream ms = new MemoryStream();
   // StreamWriter sw = new StreamWriter(stream);
    //sw.Write();
   // sw.Flush();
    stream.ToArray();
    Attachment data = null;
    MessageBox.Show(stream.Length.ToString());
    byte[] contentAsBytes;
    // FileData holds byte[] that is the contents of the file
    contentAsBytes = stream.ToArray();
    stream.Write(contentAsBytes, 0, contentAsBytes.Length);
    stream.Seek(0, SeekOrigin.Begin);
    // content type for file info
    ContentType contentType = new ContentType();
    contentType.MediaType = MediaTypeNames.Application.Octet;
    contentType.Name = "test";

    ContentType contenttype = new ContentType();
    contenttype.MediaType = MediaTypeNames.Text.Html;
    // Create  the file attachment for this e-mail message.
     data = new Attachment(stream, contenttype);
         message.Attachments.Add(data);

    //Send the message.
    SmtpClient client = new SmtpClient("smtp.gmail.com");
    // Add credentials if the SMTP server requires them.
    client.Credentials = CredentialCache.DefaultNetworkCredentials;
    try
    {
        client.Send(message);
    }
    catch (Exception ex)
    {
        Console.WriteLine("Exception caught in CreateMessageWithAttachment(): {0}",
              ex.ToString());
    }
    // Display the values in the ContentDisposition for the attachment.
    ContentDisposition cd = data.ContentDisposition;
    Console.WriteLine("Content disposition");
    Console.WriteLine(cd.ToString());
    Console.WriteLine("File {0}", cd.FileName);
    Console.WriteLine("Size {0}", cd.Size);
    Console.WriteLine("Creation {0}", cd.CreationDate);
    Console.WriteLine("Modification {0}", cd.ModificationDate);
    Console.WriteLine("Read {0}", cd.ReadDate);
    Console.WriteLine("Inline {0}", cd.Inline);
    Console.WriteLine("Parameters: {0}", cd.Parameters.Count);
    foreach (DictionaryEntry d in cd.Parameters)
    {
        Console.WriteLine("{0} = {1}", d.Key, d.Value);
    }
    data.Dispose();
}