From this to this
Note: Its hideous, i know, i did it in 5 mins.

Credit: *acaraluv @ Deviantart
1. Open your image and make a new layer on top (Ctrl + J)
2. Zoom into the image as much as you need and start to trace around the outline, just as the image about states. Once you're done tracing that particular part press: Ctrl + anywhere on the canvas and then start on your next line. It'll look something like this
3. Once you finish tracing the whole image repeat the step above: Ctrl + anywhere on the canvas
4. Go to your paintbrush tool and select a size 3px Solid Round Brush. Click the pen tool again > Right Click > Stroke Path > Set to Brush. Make sure Simulate pressure is checked! Then click okay.
5. Repeat step four but select a size 2px Solid Round Brush
6. Repeat step four but select a size 1px Solid Round Brush. But make sure Simulate Pressue is unchecked!
And thats pretty much it.
Other examples:

--Kathy




































