Winform下pictruebox控件加载网络图片

1 string s = "http://www.google.com/intl/zh-CN_ALL/images/logo.gif";
2 System.Net.HttpWebRequest req = (System.Net.HttpWebRequest)System.Net.HttpWebRequest.Create(s);
3 System.Net.HttpWebResponse res = (System.Net.HttpWebResponse)req.GetResponse();
4 this.pictureBox1.Image = Image.FromStream(res.GetResponseStream());