When working on shared or managed systems, preferences for applications may not always work as expected. When attempting to share your iPhoto Library, for instance, you may find that preference is not available due to settings in Workgroup Manager.
Apple Support Discussions user RabbitSF posted:
We have 17 latest Mac Minis in our school lab and I want to have one machine share its iPhoto library over the network. So I went to open the iPhoto Preferences, then Sharing tab, checked Share My Photos and Share Entire Library, but the Status still says Off.
Sharing your iPhoto Library is much like sharing your iTunes Library. Users connected to the same network are able to view your photos, albums, and any projects you allow. To enable sharing, navigate to the iPhoto menu bar, click iPhoto, then Preferences.
In the Sharing tab, check the box to "Share my photos." You can choose to share your entire library or select specific folders and projects to be viewable. You can also choose a name for your shared library and require a password. Now, your iPhoto Library will appear in the iPhoto sidebar of any connected users that are searching for iPhoto Libraries.
Because the computer in question was being managed by Workgroup Manager on the network, the default preferences for iPhoto were defined remotely--to not allow iPhoto Library sharing. To rectify the problem, simply delete the iPhoto preference file (com.apple.iPhoto.plist) from the Workgroup Manager preference list.