On an iPhone, when you double-tap your home button, it brings up the app switcher, which shows you all the apps that are currently running. But the thumbnail that is displayed when switching apps is not necessarily what those apps currently have showing. Some are "live" and some are not, and I don't know how iOS decides what to display, nor how often it updates the thumbnail cache.
A while back, my girlfriend sent a pic of herself to my Gmail account, which is... umm... not exactly safe for work if you catch my drift. Anyway, that was almost 6 months ago, but to this very day that's the picture that shows every time I bring up the app switcher if I don't close the Gmail app when I'm done using it.
While I certainly do appreciate the picture, this has led to several awkward moments when there are other people around. She's not exactly fond of it either. The thumbnail has survived two iOS updates and I've power-cycled the phone numerous times since then. I even uninstalled/reinstalled the app. I figured it would've updated the thumbnail cache on its own by now, but as I said before, here we are 6 months later and that picture is still stuck there.
Is there any way to get iOS to flush the thumbnail cache?
