There are some situations, such as when an iPhoto library gets corrupted, when your photos may still exist inside your iPhoto library, and you can still see them in the Finder, but they don't show up in iPhoto. iPhoto Library Manager's photo extraction feature makes it simple to copy all your photos out from such a library.

To extract photos from a library, select that library in the list and select "Extract Photos..." from the File menu. You will be prompted to create a folder into which all the extracted photos will be copied. An option in the preferences allows you to also copy originals from the iPhoto library. If this option is enabled, then any originals found in the library will be copied into a subfolder titled "Originals".

See also:

Rebuilding An iPhoto Library