That's incredibly cool! The only thing is that 
loading time is just huge for me and everytime I 
move the mouse over a pic, the other pic reloads 
so it's a constant loading cycle. You might want 
to put a statement at the top of your page to let 
people know you have the second "hidden" picture 
so they stick around to see them.

I'm not sure what I would suggest to help with 
loading time (could be my crappy internet 
connection) but I'm all for looking at 
screencaps! 

Good luck,

Wendy