Ok so i bought a iPhone 4S off craiglist. He upgraded to the iphone 5 since he showed it to me. Anyways i saw that in the screen their seems to be some sort of a shadow. I can really explain it but you can see it only on a blank screen. Anyways i checked to see if the iPhone 4S still had warranty and it has warranty until April of 2013. So my question is if i can use the warranty or am i going to have to show proof that I'm the original owner to use the warranty? Or can i just go to the apple store and they just look up my IMEI and see it still has warranty? I also factory unlocked my iPhone 4S on ebay i don't know if that's also going to effect my iPhone 4S. And no it's not jailbroken just factory unlocked.