This effect was generated in Filter Forge, a Photoshop plugin that allows you to create your own filters.
Put a pointillist effect on an image.
Choose which channel to affect- 1(R), 2(G) or 3(B).
Adjust the size of the points with Point Size 1 and 2 (one affects the darks, the other the lights).
Blend the two different dot sizes together with Threshold.
Control dots with Dot Strength, Dot Variation.
Change dots from square to round with Dot Roundness.
Choose Blend Mode and Opacity of the different dot layers.
Can also change Hue, Saturation and Gamma and choose to Blend with the original image.
paint dots pointillism art abstract creative dot painterly