Read:
http://scottjehl.github.io/picturefill/
You don't need anything to view the demo, just mount the directory and open up the index.
But if you want to play around with it then have ImageMagick installed, ruby, gem, bundler.
Run bundle install, open thumbnails.rb, do whatever modifications you want there and on the index.
Execute thumbnails.rb to generate your new thumbnails and check out your index.