Download: Comic Coloring Effect Action
Before and After Image
Read more for guidelines on how to use the action.
Tips: Always start with a large image and resize it if necessary after you run the action.
Open your image in Photoshop and make sure your layer palette looks like the picture below ie. (a)only one layer, (b)it should be named 'Background' and (c)it should be locked with a sophisticated lock symbol on the side. Click on the 'Background' layer on the layer palette to select that layer and run the action.
If for some reason, above is not the case for you, here's what you can do to achieve the correct starting point for the action: