Broke my sprint phone, will I be able to unlock and use an AT&T one?

[dinosaur]

Yesterday my friend dropped my sprint iPhone 4s in a pool. I put it in a bag of rice and nothing happened. it seems completely dead, so I'm going to have to get a new phone. My grandma has an AT&T iPhone 4 and she is up for and upgrade which she won't use, so she probably will let me use it. If we were to upgrade and get an iPhone 5, would I be able to unlock either the new iPhone 5 or the old 4 and use it on sprint legally? thank you for you help!

 

[dinosaur]

I also have lots of important pictures from the past few months that I didn't back up.. Is there anyway to get them back? I have never used iCloud

 

[willerz2]

You'd have to get one from Sprint, otherwise, you'd have to pay full price for the 5 at Apple, and bring it to Sprint for them to activate. As for the data on the device, most likely no. Recovering data from a broken/drowned phone requires professional equipment. You can see whether or not a local Apple Store can retrieve any or all data from the drowned device for you to restore onto your new device.