Bitmap bmp = new Bitmap(800, 600); ลบจุดไม่ได้ ผมควรทำไงดีครับ ช่วยหน่อยนะครับ

            for (c = 1; c <= cx; c++)
            {

                string[] arr = MyRecord[c - 1].ToString().Split('|');

                XM = arr[0].ToString();
                YM = arr[1].ToString();
                XCM = System.Convert.ToInt32(arr[0]);                                       ////
                YCM = System.Convert.ToInt32(arr[1]);
                {
                    Bitmap bmp = new Bitmap(800, 600);
                    using (Graphics g = Graphics.FromImage(bmp))
                    {
                        SolidBrush s = new SolidBrush(Color.Yellow);
                        g.FillEllipse(s, XCM - 5, (YCM - 600) * -1 - 5, 10, 10);
                    }
                    this.pictureBox1.Image = bmp;
                }
            }