C# 下载网页中的图片

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.IO;
using System.Net;

namespace WebPicture
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create("http://img2.cache.netease.com/cnews/2011/3/21/201103210158057258d.jpg");

            HttpWebResponse res = (HttpWebResponse)req.GetResponse();
            Stream s = res.GetResponseStream();

            Bitmap bmp = new Bitmap(s);
            pictureBox1.Image = bmp;
            s.Close();
        }
    }
}