So I took my laptop on vacation. I imported photos onto it and tagged the faces there. Now I'm at home and I burn an iPhoto backup DVD of the pictures so I can put them in my desktop's main iPhoto library. All of the faces data doesn't come through...all the people are 'unnamed' again. On the DVD there is a file called face.db. What is that, if it's not backing up the face data? Am I doing this wrong? Do I really need to re-name the faces in all 2,000 photos?