All hail the deer deity.
You can buy it as a shirt and a bag and stuff here.
Make the size "pixel" you want via drawing a large square [select tool helps a lot] then copy and paste it into a large checkerboard that covers your canvas. Lower the opacity, open a new layer, and simply use the bucket tool to fill in what colors you need! When you apply shading on top, move the checkerboard you originally made over the layer you're working on and continue to use the bucket tool!
Link
RedFiretrucks
THATS SO COOL!!
ps how do you do those kind of pixels??