If you sync your iPhone to iTunes or iCloud before and make backup, it is two ways for you to recover the photos from iPhone. I: Directly Recover Deleted Photos from iPhone 4/3GS II: Recover Photos from iPhone 5/4S/4/3GS from iTunes Backup
If your iPhone was damaged in water, you should: 1) Remove it from the water immediately. 2) Turn the iPhone/iPad/iPod off. 3) Dry it off with a towel. Note: Do not dry it off with a blow dryer as this could melt the circuit board and other parts. 4) Put iPhone/iPad/iPod in a bunch of silica packets, or in the bowl of uncooked rice and cover it up. 5) Leave the device in the rice for at least 24 hours and preferably 48 hours. Hopefully, after 24 - 48 hours iPhone/iPad/iPod will have dried out, the logic board wasn’t damaged, and hopefully you can turn it on and the device will work. If not, your next option is to see if it can be repaired without much cost.