Turn any photo into a dot grid artwork with these Photoshop actions. You'll get great results with dots that change size. They get larger in brighter areas and smaller in darker areas. Free download available.
Create a new Brightness/Contrast Adjustment Layer (Layer > New Adjustment Layer > Brightness/Contrast) and use the settings shown below to boost the contrast a bit.
Let’s add more soft contrast and boost the intensity. Create a new layer from all the visible layers and apply a 150px Gaussian Blur. Change the blending mode to Soft Light and lower the fill to 51%. You’ll see that the effect is too strong in some areas (black regions over the eyes for example) so add a layer mask and hide those regions with a round soft black brush until the final result looks good.