how to turn pixelated images to nice clean colored dots

convert background to smart object.. name background photo then in the upper right corner hit the drop down and convert layer to smart object
click newfill adjustment icon at bottom of layers and select solid color and choose black or any color you want for behind dots. drag your black layer below your main image so it will be behind the dots
then make sure your main image is selected then go to filter, pixelate, and then mosiac. adjust the size of the squares to the size you want your dots to be. I chose 60
then open up new document to make your dot. set the pixels per square inch to 60 because that is the same size you just set the squars to be. set background to white
use selection to make your dot. go all the way to the edge. fill with black then inverse to make dot white. then go to edit and define pattern
back in main document make sure main photo layer is selected then hit the add layer mask icon. this will put white square next to your main photo, make sure the square is selected then go to edit and hit fill. set it to pattern fill and select the circle you just made hit okay and it will fill your document with circles
to bring out the circles more we have to stroke them. make sure that same added layer mask is still selected and hit the add layer style icon at bottom of layers panel. choose stroke. in the stroke diolog box choose black color. set px to one or whatever size you want the stroke to be then set to Inside. hit okay
to bring out the colors hit the new adjustment layer icon at bottom of layers and select vibrance.... adjust vibrance.
image may be to dark so to brighten it up hit the new fill adjustment layer again and select levels. set blend mode from normal to screen. if its too bright, set opacity to 50 or 75 percent