I have my pictures Library in the Shared folder and set up using ACLs so that both my wife and I can access the photos in iPhoto. iTunes can see the albums in this location but if I try to sync my iPhone using my wife's account (trying to troubleshoot my parent's two iPhone, two user account problem with photos), then iTunes won't see any pictures. If I launch iPhoto in her account, then iTunes figures it out, only now it can't see the photos from my account! Launching iPhoto from my user account switches it back again. Weird.