This is effect adds a pixelated effect on your images.

1. Firstly open your image. I am going to be using this image of Rihanna Fenty. If you would like copy this image so you can follow along.



2. Now go to Layer > Duplicate layer.
3. Select Filter > Pixelate > Mosaic. Change the settings to 18 for cell size, but you can experiment with whatever size you like.
4. Last step, change your blending mode to overlay and change the opacity, I have used 46%.
5. Here is my result