upload image using the WebRequest

[jason213123]

hi,
i need to upload a image to a site by using
the WebRequest so far i have this for send values:

 Dim request As WebRequest = WebRequest.Create(site_name)
request.Method = "POST"

 Dim byteArray As Byte() = Encoding.ASCII.GetBytes(post_value)
 request.ContentType = "application/x-www-form-urlencoded"
            request.ContentLength = byteArray.Length
            Dim dataStream As Stream = request.GetRequestStream()
            dataStream.Write(byteArray, 0, byteArray.Length)
            dataStream.Close()
            Dim response As WebResponse = request.GetResponse()
            dataStream = response.GetResponseStream()
            Dim reader As New StreamReader(dataStream)

            Dim responseFromServer As String = reader.ReadToEnd()

            reader.Close()
            dataStream.Close()
            response.Close()

 MsgBox(responseFromServer)

but for send a image i have no ideia how do, i have looking for samples but
i only find for c# and i need this for vb.net

what i need change in my code to upload images to?
and other question how can i send cookies to the page?
thanks a lot for your help