Desktop photo from iPhoto does not appear in iPhoto
MacBook Pro, approximately one year old, OS 10.8.5 and iPhoto '11
In System Preferences>Desktop and Screen Saver, I have the Desktop set to use iPhoto, changing randomly every 1 minute. Some photos it uses are not photos that appear anywhere in iPhoto. Today I saw one go by that I want to access and use for other purposes, but it's not in iPhoto! Could the Desktop rotation be accessing photos in some other form?