Can't share photos from iPhoto to iCloud
I am trying to share photos from within iPhoto to iCloud.
When I select a photo and click "Share", none of the share option (including) iCloud are selectable.
I made sure that in "System Preferences" the "Photo" option is selected, as well as "Photo Sharing".
This is on an iMac running OS X Mavericks and iPhoto version 9.5.1.
This feature worked before on this machine, and it still works on my MacBook (same OS and iPhoto versions).
Any ideas?
OS X Mavericks (10.9.2)