At start create a new WCF service in .net 4.0 and add Azure reference to it. You can follow the guide at here.
Now instead of saving text we are going to save Pictures.
So lets start by creating two new functions. They will be SavePicture and RetrievePicture.
After that you need to edit the Web.config file.
So the secret lies on editing the Web.config file.
After that you can just publish it into Azure websites and use it.