I use the ‘Cutout’ filter for a posterized or graphic effect. I usually set the ‘Number of Levels’ (which is actually the number of colours/tones) to 8 (the highest). I keep the ‘Edge simplicity’ low (1) and then play around with ‘Edge fidelity’ until I get the look that I want.
original photo
For more on Fave Photoshop filters: http://www.albatz.com/photos/faves_plus/filters.html
The filter was nicely applied on this image. It’s an effect I try to achieve with my illustrations. Thanks for sharing!