Open up your picture in Photofiltre and go to Image >> Duplicate your picture 3 times so that you have 4 copies.
For each copy go to Adjust >> Swap RGB Channel and pick a different setting for each picture.
For each copy go to Adjust >> Posterize and set the Level to 25%.
For each copy go to Adjust >> Dithering. Then go to Edit >> Fade Dithering and set the opacity to 10%.
Then open up a new blank picture and place each picture on top of each other so that it looks like my “after” result.