Share Alike: If you want to distribute alterations of an image — if, for example, you crop it to put it on your card, you have to allow others to freely use YOUR image, too. It’s sort of a pay-it-forward condition.
Noncommercial: You cannot use any Noncommercially licensed images for your business. No exceptions.
No Derivative Works: You can use these images only if you do not change them in any way.
These four conditions make up six different kinds of Creative Commons license: