Help please !

Hi, hope someone can help. My iMac has got stuck in a process, I accidentally told it to copy 16,000 photos from iPhoto to my desktop... Now when I log in it keeps trying to copy and won't let me stop it and is not responding. I can log in as a different user and all works ok.... Any ideas?
iMac, Mac OS X (10.7.3)

Force quit iPhoto and/or Finder?

Log in as admin to another account, then move your photos from your library (or the entire library) temporarily to a different location on the same disc. Log in back to your account and see what happens. Possibly finder could give you an error now and stop trying to do the copying.

The question I have.... is why are you even storing 16,000 photos on your Mac? If your hard drive crashes or a problem occurs and you don't have a backup, you will lose all those photos. Get them off your Mac and store them on an external hard drive or to DVDs. Photos of family, weddings, baby, etc, are invaluable and can not be replaced if lost, so be sure to always back them up.