c#get网页图片并显示在picturebox上

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.Diagnostics;//Trace.WriteLine
using System.Net;
using System.IO;

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

        private void button1_Click(object sender, EventArgs e)
        {
            Encoding encode = Encoding.GetEncoding("utf-8");//网页编码==Encoding.UTF8
            //GET /img/baidu_jgylogo3.gif HTTP/1.1
            //Accept: image/png, image/svg+xml, image/*;q=0.8, */*;q=0.5
            //X-HttpWatch-RID: 46990-10314
            //Referer: http://www.baidu.com/
            //Accept-Language: zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3
            //User-Agent: Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko
            //Accept-Encoding: gzip, deflate
            HttpWebRequest req = (HttpWebRequest)WebRequest.Create(new Uri(@"http://www.baidu.com/img/baidu_jgylogo3.gif"));
            req.Method = "GET";
            req.UserAgent = " Mozilla/5.0 (Windows NT 6.3; Trident/7.0; rv:11.0) like Gecko";
            //req.ContentType = "application/x-www-form-urlencoded";
            req.Accept = "image/png, image/svg+xml, image/*;q=0.8, */*;q=0.5";
            req.Headers.Add("X-HttpWatch-RID", " 46990-10314");
            req.Headers.Add("Accept-Language", "zh-Hans-CN,zh-Hans;q=0.8,en-US;q=0.5,en;q=0.3");

            HttpWebResponse ress = (HttpWebResponse)req.GetResponse();
            Stream sstreamRes = ress.GetResponseStream();
            pictureBox1.Image = System.Drawing.Image.FromStream(sstreamRes);
        }
    }
}