I think you cannot disable it once you activate it since 1020 is supposedly not to get this feature. Luckily there is a way: uninstall and re-install your nokia camera. I have tried it just now and it works.
@AntZoo Living images can be activated in 1020 if you are using nokia camera beta (not sure about recent version of nokia camera since I haven't tested it yet). Open it then go to settings and then choose "use default settings" on the bottom of the screen. Some people say it doesn't work but some work including mine. If it works, once you take a picture, it will show 'saving living images' but you can only see it only in nokia camera.