HELP???

Hey Everyone,
I am trying to update my website and I am having a very difficult time. I used dreamweaver to create it, but so many different people are telling me that sometimes the thumbnails work and sometimes they dont. I wound up deleting a bunch of stuff to start fresh, and I am trying to figure out the mouse over/mouse double click thing to get the image to show up. I know there has got to be an easier way than what I am doing to get rid of all the gliches. If any of you know anything about this I would really appreciate it. thanks so much!!! the old website is still up