You can move you images from your photo stream and camera roll to projects and folders that are synced with iTunes.
You can also now delete items directly from your idevice rather than the old 4.2 way of having to sync to achieve deletion.
You can mail /tweet / FB your images directly from the iphone or ipad too.
Overall, IOS6 gives you a lot more control over your image libraries than IOS4 ever did.
Used in conjunction with an app like Goodreader, you can also move files around your network too.