You may be able to repair the phone by 'replacing the battery and cleaning the logic board and other parts such as the cable connections with 90% or higher isopropyl alcohol and a small soft bristle brush such as a toothbrush. This helps remove conductive and corrosive minerals left behind by water and other liquids when they dry. The battery is usually the first thing to fail when water damage occurrs.
There are guides on this site and plenty of instructional videos on YouTube that can show how to clean with isopropyl alcohol. This may be able to revive the phone so you can retrieve the photos yourself.
I do believe there are ways to retrieve data from a dead phone but they can be quite expensive and very technical. JTAG is one I know of.