求助二进制存储图片参数无效

            int with = panel1.Width;
            int height = panel1.Height;
            Image im = new Bitmap(with, height);
            Graphics g = Graphics.FromImage(im);
            //g.CopyFromScreen(this.PointToScreen(new Point(0, panel1.Height)), new Point(0, 0), newSize(with,height));

            g.CopyFromScreen(this.PointToScreen(new Point(0, 0)), new Point(0, 0), new Size(with + panel1.Width, height + 50));

            g.Dispose();
            im.Dispose();




            string sql = string.Format("update userinfo set pic=@img  where id=" + DB.id+ "  ");

            SqlCommand cmd = new SqlCommand(sql, DB.con);

            //设定参数的类型为image
            SqlParameter prm = new SqlParameter("@img", SqlDbType.Image);

            //内存流
            MemoryStream ms = new MemoryStream();

            //image对象
            System.Drawing.Image img = im;

           //这里提示错误为: 参数无效  请问那里出错了
            img.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);
            prm.Value = ms.GetBuffer();
            cmd.Parameters.Add(prm);
            DB.con.Open();

            //添加到数据库的sql语句

            int i = cmd.ExecuteNonQuery();
            if (i == 1)
            {

            }
            DB.con.Close(); --------------------编程问答-------------------- 自己找到问题了
  im.Dispose();


应该放到最后； --------------------编程问答-------------------- 解决了的话我是来接分的

补充：.NET技术 ,  C#

求助二进制存储图片 参数无效

求助二进制存储图片参数无效