Sharing photos in iPhoto is more complex than sharing music in iTunes because iPhoto is more particular about where its files live, and because all users need read-and-write access for importing and editing purposes.
You must choose between two approaches to sharing photos in iPhoto: what I term the "shared iPhoto Library" approach, or the iPhoto Sharing approach:
Use the shared iPhoto Library approach to share photos when you need to ensure that all networked users can import, view, organize, and output the same set of photos. The shared iPhoto Library method is best for people who want to mix all their photos and work on them together. For info on setting up this approach, see Share an iPhoto Library, next page.
Use the iPhoto ...