private string file = string.Empty;
        protected void Page_Load(object sender, EventArgs e)
        {
            file = Request.QueryString["imgFile"].ToString();
            FileStream stream = new FileStream(file, FileMode.Open);
            //获取流的的长度
            long FileSize = stream.Length;

            byte[] Buffer = new byte[(int)FileSize];
            stream.Read(Buffer, 0, (int)FileSize);
            stream.Close();
            Response.BinaryWrite(Buffer);
            stream = null;

        }