Mysteriously, while using my phone in any app, my back button will lock up from time to time for a minute or so, during which the home button acts as a screen capture button with shutter noise. Unable to find the pictures as well. It happens in any app and hijacks it while I'm stuck in the app that got hijacked by something in background.
I've since installed ATK - advanced task killer to identify what's running during my issue and sure enough I see the default Android app called Gallery running but I don't see Gallery in the foreground. Android Task manager doesn't show it running but ATK sees it running. So, I force close it and everything works again usually. At any given time Gallery will silently auto start without my knowledg, sometimes even right after I force closed it. Creepy if someone is watching me remotely as I'm aware of silent apps that can do so (which I've never used). I'm confident that rooting the phone will resolve this to be able to take full control back but it may affect my warranty. So annoying.
Also if I try to force close the default Samsung app called Y! Finance Clock, then my back and home button issue reappears every time. Strange.
Samsung galaxy s vibrant -Bell mobility
froyo 2.2