smartcrop.js is a content aware image cropping library. On this page you can see how it operates on a large set of (>100) images. This page is designed to show you both the strengths and weaknesses of this open source library. You can learn more about the library on it's github page. You can try it out on your on images using the testbed
Me by Myself ;)
Cats in the Spring by ziamoku_woodpile
Kitty, Daisy and Lewis at the Garage by Paul Hudson
Where Have All the Good Times Gone? by N. Feans