1. You were working on a file in photoshop when everything shut down and the only version of the file you have is .jpg and not .psd?
if so, there will be nothing you can do about that. You will need to redo whatever you had done in photoshop before the shutdown. This is a great learning lesson to save often. It's fast and easy. ctrl + S.
2. When you are working with photoshop the only option for saving pictures in is .jpg?
How are you trying to save images? File-->Save for web & devices or file-->Save As?