iPhoto may update picture thumbnails
When you update to iPhoto 4 or later, iPhoto may ask you to update the library's thumbnails when you open the application.
Products Affected
iPhoto
This is normal. Updating rebuilds the thumbnail files for improved quality and reliability with the newer version of iPhoto. If you choose not to update the thumbnails, you will be prompted again the next time you open iPhoto.
iPhoto libraries burned to CD or DVD are not affected by this change.
iPhoto libraries burned to CD or DVD are not affected by this change.