
If you own an iPod, iPhone, or Apple TV, you can use iTunes to sync the photos from your iPhoto library so that you can view them on any of these devices. If you have multiple iPhoto libraries set up though, you can only sync the contents of one of your libraries at a time. When you sync your device in iTunes, it will sync the photos from whichever library you currently have selected as the active library (i.e. the one that would appear if you opened iPhoto). If you switch libraries between syncs, this can result in the photos on your device being replaced with those from another library, which may not be desired.