C# 通过URL获取图片并显示在PictureBox上的方法

string url = string.Format(@"http://q1.qlogo.cn/g?b=qq&nk=8583048&s=100", 5, 123456);
System.Net.WebRequest webreq = System.Net.WebRequest.Create(url);
System.Net.WebResponse webres = webreq.GetResponse();
using (System.IO.Stream stream = webres.GetResponseStream())
{
pictureBox1.Image = Image.FromStream(stream);
}