Not your average pixel effect tutorial, let me show you a nice little trick where you apply the normal square pixelated effect and turn it into checkered, diamond looking photo pixels.
Remember the legendary Predator movie with Arnold Schwarzenegger? Those Predator aliens had this thermal view feature so they could their prey even in complete darkness, let's Photoshop it.
A simple Photoshop tutorial, where you may learn how to expose an object by leaving it in color while turning the rest of the photo black and white or sepia.