Picasa's Filtered Black & White Feature

This is a great example of the beauty of Picasa's Filtered Black & White feature. Below you see the original color image of Yong in plank position. His eyes are closed and his face has a wonderful expression of concentration. Unfortunately, his face is reflecting red from the red gym mats just outside of the shot (see Sno-Cones post).
  Original color

If I just use the basic black & white feature on Picasa, I lose the detail of his face in shadow, below. Unacceptable.
  Black & White

However, if I use the Filtered Black & White feature, I can select a color filter that lightens his face and helps to isolate his expression (in this case, a red filter). Much better.