Copying an image from URL to folder

using System.Net;
using System.IO;
using System.Drawing;
using System.Drawing.Drawing2D;

string url = "http://www.codeproject.com/App_Themes/Std/Img/logo225x90.gif";
        Bitmap b;
        Uri uri = new Uri(url);
        WebRequest webRequest = (HttpWebRequest)WebRequest.Create(uri);
        using (HttpWebResponse webResponse = (HttpWebResponse)webRequest.GetResponse())
        {
            using (Stream stream = webResponse.GetResponseStream())
            {
                System.Drawing.Image img = System.Drawing.Image.FromStream(stream);
                img.Save(Server.MapPath(Guid.NewGuid().ToString() + ".jpg"));
                img.Dispose();
            }
        }