Rod, how did you get the small dots to go around the brim of the hat and bow? Did you select them separately? Also, it looks transparent, Did you remove any white before you ran the script?
I just used the default settings for that image Molly.It started out as an indexed black and white image.
I believe if the image has more contrast (such as his hat and the bg) colors.The lines of circles follow the edges more.
Actually because they are two different colors and the circles are each one solid color it seems that way to the eye.
All i did to the image was change the image mode from indexed to RGB, flattened the image.
I ran the Circlism filter after that and got those results.
So the more contrast in an image the more your going to get those type of edge results i think.