Currently Being ModeratedSep 13, 2013 5:03 AM (in response to marco8055)
You can have as many libraries as you like but you can't have any of them on a NAS.
To create a new Library:
Hold down the option (or alt) key key and launch iPhoto. From the resulting menu select 'Create Library'
To choose between Libraries:
Hold down the option (or alt) key key and launch iPhoto. From the resulting menu select 'Choose Library'
To move a Library:
Make sure the drive is formatted Mac OS Extended (Journaled)
1. Quit iPhoto
2. Copy the iPhoto Library from your Pictures Folder to the External Disk.
3. Hold down the option (or alt) key while launching iPhoto. From the resulting menu select 'Choose Library' and navigate to the new location. From that point on this will be the default location of your library.
4. Test the library and when you're sure all is well, trash the one on your internal HD to free up space.
On the subject of NAS:
iPhoto needs to have the Library sitting on disk formatted Mac OS Extended (Journaled). Users with the Library sitting on disks otherwise formatted regularly report issues including, but not limited to, importing, exporting, saving edits and sharing the photos.
See this article
for more. Note also the comment:
“Additionally, storing the iPhoto library on a network rather than locally on your computer can also lead to poor performance or data loss.”