Do you have an grey screen exclamation mark in iPhoto?

Probably because of doing something like this: It is strongly advised that you do not move, change or in anyway alter things in the iPhoto Library Folder as this can cause the application to fail and even lead to data loss.  Thanks Terrance.

• How to fix this problem.
• To create and populate a new library:
• Note this will give you a working library with the same Events and pictures as before, however, you will lose your albums, keywords, modified versions, books, calendars etc.
• In the iPhoto Preferences -> Events Uncheck the box at ‘Imported Items from the Finder’
• Move the iPhoto Library to the desktop
• Launch iPhoto. It will ask if you wish to create a new Library. Say Yes.
• Go into the iPhoto Library (Right Click -> Show Package Contents) on your desktop and find the Originals folder. From the Originals folder drag the individual Event Folders to the iPhoto Window and it will recreate them in the new library.
• When you’re sure all is well you can delete the iPhoto Library on your desktop.