Preview is freezing repeatedly

I'm running a new iMac with OS X Lion 10.7.4. Whenever I open the application Preview, it goes to fullscreen and stops responding (presenting the rainbow wheel) for a number of minutes. This happens everytime the scanner scans a file and opens in on Preview, and oftentimes when the application is opened normally. It takes about 5-10 minutes for it to begin responding after opening it. I know Preview is a relatively lightweight application, so why is it causing such problems?

Any ideas on how to fix it?