TS4379: iCloud: Troubleshooting iCloud Photo Sharing and Shared Photo StreamsLearn about iCloud: Troubleshooting iCloud Photo Sharing and Shared Photo Streams
Currently Being ModeratedJun 30, 2013 6:54 PM (in response to RedskinRay)
I'm afraid not as photo stream photos are only kept in iCloud for 30 days (even though up to 1000 will remain on your device until deleted...such as by restoring). Once they're deleted from iCloud they are permanently gone.
Camera roll photos are stored in your backup. If the photo stream photos were still in the camera roll, restoring the entire backup should recover them.