Welcome to Android Central! That's unfortunate. Android doesn't routinely back up data to your SD card, unless you have a specific app that is designed to do that. SD cards are not foolproof anyway--they can get corrupted somewhat easily, and they don't last forever.
It's hard to know what's on your card if neither the phone nor the laptop can reliably read it. That also suggests a corrupt card or corrupt files. You could try running chkdsk to see if there are bad sectors:
http://forums.androidcentral.com/amb...d-sd-card.html
The fact that the water indicators were tripped does suggest that moisture was the cause of the phone's failure. The damage from moisture doesn't always occur right away--it can set up corrosion that takes days to weeks to cause problems.
Any photos on your phone's internal storage are probably lost. You'd probably have to contact some kind of forensic tech specialist to try to retrieve them. Sorry!