NexusGirlX already replied that you do, but also remember that factory resetting wipes out your entire device. This means all files, pictures, documents... EVERYTHING on the internal memory is gone. So back things up first before doing that or you'll lose all information and documents! (Unless you're already backing things up automatically to a cloud service... and if you're not, you should, at least with camera pictures. Trust me on this one. And since uploading to your Google account with a still-very-acceptable quality, around the equivalent of a 3MP picture, is totally and completely free, there's really no reason not to. And if you want the full-size back up, you can still do it but that will count against your Drive quota).