All photos are gone after updating my iPhone to iOS 5
According to Apple, iTunes should automatically backup your photos and videos:


  Backed-up information includes purchased music, TV shows, apps, and books*; photos and video in the Camera Roll; ...


However, the format of the backup doesn't make it easy to access those photos. Therefore, you can use a program such as iPhone Backup Extractor which should make it a lot easier to recover data from the backup, including photos. I haven't tried the app, so I can't personally recommend it, but it did get good reviews on CNET.