ช่วยด้วยครบ imageUrl ไม่ยอมแสดงภาพเลย ไม่รู้จะแก้ยังไง รบกวนด้วยนะครับ

  System.Drawing.Bitmap image;
            image = new System.Drawing.Bitmap(Server.MapPath("2.jpg"));
            Color c;
            for (int i = 0; i < image.Width; i++)
            {
                for (int j = 0; j < image.Height; j++)
                {
                    c = image.GetPixel(i, j);
                    int r = 0;
                    r = Convert.ToInt16(c.R);

                    int g = 0;
                    g = Convert.ToInt16(c.G);

                    int b = 0;
                    b = Convert.ToInt16(c.B);

                    int ans = (r + g + b) / 3;
                    if (ans > 125)
                    {
                        r = 255;
                        g = 255;
                        b = 255;
                    }
                    else
                    {
                        r = 0;
                        g = 0;
                        b = 0;
                    }
                    c = Color.FromArgb(r, g, b);
                    image.SetPixel(i, j, c);
                }
            }

         System.Drawing.Graphics G = System.Drawing.Graphics.FromImage(image);
            //System.Drawing.Image bitmap2 = (System.Drawing.Image)Bitmap.FromFile(Server.MapPath("tham1.jpg"));

           //G.DrawImage(bitmap2, (image.Width - bitmap2.Width) / 2, (image.Height - bitmap2.Height) / 2);
           G.DrawImage(image, image.Width, image.Height);

            MemoryStream stream = new MemoryStream();
            image.Save(stream, ImageFormat.Jpeg);

            String saveImagePath = Server.MapPath("ima\\2.jpg");
            image.Save(saveImagePath);        
            TextBox1.Text = saveImagePath;
            Image1.ImageUrl = saveImagePath;