Re: M2 or Moto G (2014)
Moto G has more big display - 5", 720x1280, but Xperia M2 has 1080p - 30fps video. For me more good is Moto G because it will be upgradable to Android 5.0 Lollipop.
Re: finding stock images for sony phones
Download Sony PC Companion. It automatically download and install the latest android version available for your XPERIA.