Creating a bitmap in memory with .NET

using System.Drawing;
using System.Drawing.Imaging;

class BitmapInMem {
  static void Main() {
    Bitmap bitmap = new Bitmap(800,600,PixelFormat.Format32bppArgb);
    Graphics g = Graphics.FromImage(bitmap);
    
    g.DrawRectangle(new Pen(Color.Yellow,3),10,10,700,500);
    bitmap.Save("c:\\temp\\generated.bmp");
  }
}