title: save bitmap image as grayscale image in C#
body: <p>This is my bitmap code</p>
  
  <pre><code>Bitmap b = new Bitmap(columns, rows, PixelFormat.Format24bppRgb);
  BitmapData bmd = b.LockBits(new Rectangle(0, 0, columns, rows), ImageLockMode.ReadWrite, b.PixelFormat); 
  </code></pre>
  
  <p>How can i save this as a grayscale image ?</p>
  
  <p>Well iam specifically interested in the saving part. How do i save it as a file ?</p>