So you want one of my hamsters? All you need to do is follow the rules:
1. Don't steal them. That is, don't put them on your site and claim they're yours.
2. Don't change them in any way (unless you have to make them smaller. But that's it).
3. Don't alter the code given with them unless you want to put it in the center or something. And do not remove the link given with it.
And there you have it!