layout similar to clipboard

Hi
I have upload image script. where user can upload their images. The width and height of the images are not limited. Users can upload any kind of images. Now the problem I am facing is if users upload large images and small images, the layout get scattered.
So I decided to do layout similar to

http://sergey.fantoon.com/clipboard/funny.html
here they have aligned the images very nicely. They looks prety aligned in the way of rows and columns. they are not scattered. So I would like to get exact same layout.
Any body know what scripts can help me to achieve this?
your help will be aprreciated.
thanks