Recompress old change screen screenshot with pngcrush

This reduces the size of the file by approx 35% and makes
it viewable on my Macbook Pro.

Change-Id: Ie8956ee336441ca2d9a9bff9b99d89314434da5f
1 file changed
tree: cff5656f8ca2a3bf8ab6c28251580f83f8acfec1
  1. exercises/
  2. img/
  3. presentations/
  4. .gitignore
  5. LICENSE
  6. README