What Is The Best Way To Optimize Live Website Thumbnails?

Background: I'm creating a web design portfolio of sites I've created and like the effect I can get by doing live thumbnails because certain pages are dynamic and it's nice to show

Solution 1:

I'm taking @I has kode's answer as the best option to get the effect I want. However for simplicities sake I've realized it's just not a good option to get live thumbnails and have gone back to static images for now. I'll keep this on file though when I come back to this.