This produces a color image that appears to be made up of dots. This uses the Demitone25 filter, but as that produces a mono image, the resulting image is combined with the original so that we have a color photo.
You can achieve a similar effect by duplicating the background layer and applying the Demitone25 filter to it. As mentioned, you'll see that you now have a black and white image. However, you only need to change the Layer mode of the mono layer to Overlay and instantly you have a color image that is apparently made up of dots.