I don't think you can - I have to 'synch' (if that's the right word) mine (always a faff, can never remember what to do). Still haven't got any photos on my iPad but managed to get them onto my iPhone. Do love my iPad but it such a pain in the bum really.
I have used iTunes and also I use mainly a little dongle that plugs into the iPad and you slot a camera SD card into.
Works a treat.
As soon as you plug it in the iPad fires up up the pictures as thumb nails and you select them and it imports them.
Pictures look fantastic on the iPad.
Amazing clarity
I have an ipod. I also have an easy share for a kodak camera on my computer. When I connect my ipod to the computer to charge it up it asks if I want to download photos and I usually do.