Step:1 open your image. put a selection around your image that you like to put the pop dots effect behind

Step:2 press apple+J twice. put a selection around layer 2.

Step:3 go under the selection menu, under modify, and choose expand/. enter 10 pixels and click OK.

Step:4 press "d" to switch your swatches to the default colors. options + delete.

Step:5 press the letter"q" to enter quick mask mode. go under the filter menu, under pixelate, and choose color half tone. click OK.

Step:6 keep running this filter until you are satisfied with the results. top the letter "q" to leave quick mask mode.

Step:7 option delete. deselect your image.