求一个根据图片url路径获取图片高度的方法！
rt
[最优解释]
private void button1_Click(object sender, EventArgs e)
{
WebClient wc=new WebClient();
wc.DownloadFile("http://www.baidu.com/img/baidu_sylogo1.gif","temp");
Bitmap b = new Bitmap("temp");
MessageBox.Show(b.Height.ToString());
}
