Image baseImage = new Bitmap(Screen.PrimaryScreen.Bounds.Width, Screen.PrimaryScreen.Bounds.Height);
Graphics g = Graphics.FromImage(baseImage);
g.CopyFromScreen(new Point(0, 0), new Point(0, 0), Screen.AllScreens[0].Bounds.Size);
g.Dispose();
baseImage.Save("baseImage.jpg", ImageFormat.Jpeg);