Backup Picasa 'people' tags data

From How to Back up Name Tags and copy to an another computer :

Q: Is face tag data stored in the photo itself?

A: We currently do not store face tag data directly inside the photo but this is functionality that we hope to have in the future.

Q: Since my face tag data is not stored in the photo itself, where is my face tags data stored?

A: Face tag data is stored in the Picasa database and also in the .picasa.ini file in the folder where your tagged photo sits. To see the location of the photo on your hard drive and the .ini file where the information is stored, right click the photo and select "Locate on Disk".

Q: How do I transfer my face tags from one computer to another?

A: There are a few different ways to transfer your face tags:

1) You can perform a Backup of your photos and restore them on your new computer. This process will preserve your face tags. ("Tools" > "Backup Pictures")
2) You can copy your files and the .picasa.ini file from your hard drive to the new destination
3) Upload your face tag albums to Picasa Web Albums and download the album to the new destination

*Important note on option 3: In order for your contact information to be preserved you'll need to make sure that your contacts associated with your face tags are marked as "Online Contacts." This means that the person is synchronized with Google Contacts. After copying the photos to the destination computer, make sure you are logged in to your Google user account so that Picasa can retrieve your Google Contacts and update your face tags with the corresponding information. See reference section for more info on syncing contacts.

Check out this tool called upsync faces for a different way of accessing and backing up name tags. It is written in PERL.