There are a variety of other applications that integrate with iPhoto to give you direct access to the pictures in your iPhoto library. A partial list of these applications includes:

All of these applications, however, only display a single iPhoto library. The library it displays will be whichever library is currently selected in iPhoto Library Manager as the current library. If you wish to work with a particular library using one of these applications, you should first quit the application, then go to iPhoto Library Manager and switch to the library you want to use. When you reopen the other application, the newly selected library should now show up in that application

A special note with regard to using iPhoto albums as desktop pictures or screen savers. When you select an iPhoto album to use for either of these purposes, the system will only remember the name of the album you selected, and not the location of the library that the album is in. This means that, if you have library "A" active and you go select album "X" to use for your desktop picture set, if you then later switch to library "B", the system will not use album "X" from library "A", it will instead look for an album named "X" in library "B", which of course may not even exist. If you switch libraries often but want to keep your desktop displaying the same set of pictures, you might consider creating an iPod folder that syncs with the album(s) you want to display. You can then point the desktop/screen saver to get pictures from that folder instead of from the actual iPhoto album.

See also:

The AlbumData.xml file

Switching between libraries