Some users have reported an issue in which photo libraries are blank or missing after the update to iPhoto ’11, and all of the contained images are apparently deleted.
When this issue occurs, users are presented with a list of their libraries in the iPhoto browser, but they all display blank rectangles instead of preview photos, and double clicking the albums reveals no photos.
This issue appears to be tied to another previously covered issue in which iPhoto ’11 gets stuck on the library upgrade process that occurs directly after installing the program (as part of the iLife suite). Users experiencing this problem may receive a gray screen and a spinning progress indicator indefinitely.
In some cases, you can recover access to an intact library by holding down the option key while you launch iPhoto ’11, then selecting your current iPhoto library, (located in /Pictures/iPhoto) and renaming the file.
If you don’t have a backup, you can try a data recovery tool such as Data Rescue II, File Salvage or TechTool Pro