Hi all. I have already seen other forums on here that told me how to change the pictures of my icons, but for some reason when I try to change my system preferences icon or my preview icon, my computer won't let me change either icon. For some reason both are locked [here's an example of an unlocked app and here's an example of a locked app]. What I'm saying is, I can change the icons of unlocked apps, but not the locked ones. Is there a way to unlock the locked apps or anyway to get around it or not?