thumbnail hover

hi everyone!
I’ve got this question, maybe anyone could think of a solution:
Right now my blog contains thumbnails of posts. I’d like them to fade into other images when you move your mouse on. I know it is done with javascript, and i kinda know how. the problem is i need different images to appear on different thumbnails (example is smth like this http://www.stewarttraverdesign.com/#)
However, this is done for a static web-site. And I’ve got a blog, so another problem is that my thumbnails are in the loop and i do not even know where to paste the javascript code.
any help is appreciated!