asp.net 下载图片

//引用using System.IO;  //button事件protected void Button3_Click(object sender, EventArgs e)    {        string fileName = "123.jpg";//客户端保存的文件名        string filePath = Server.MapPath("images/1.jpg");//路径        //以字符流的形式下载文件        FileStream fs = new FileStream(filePath, FileMode.Open);        byte[] bytes = new byte[(int)fs.Length];        fs.Read(bytes, 0, bytes.Length);        fs.Close();        Response.ContentType = "application/octet-stream";        //通知浏览器下载文件而不是打开        Response.AddHeader("Content-Disposition", "attachment;  filename=" + HttpUtility.UrlEncode(fileName, System.Text.Encoding.UTF8));        Response.BinaryWrite(bytes);        Response.Flush();        Response.End();    }