Hello, been lurking about and learning while awaiting my first snake purchase.
I can post on this topic however, as it is my field of expertise.
The original "cartooning" image in this thread is not just sharpened. It looks like daveb's image editing application performed several operations to achieve the final image there. Most probably, some sort of posterization(throwing away colors and gradation to achieve a blocky result). Then a slight bluring, and finally an edge detection filter of some sort. Basically one that darkens the edges of colors to near black.
It's hard to tell exactly which algorithms were used to achieve the final image as different software packages do similar things differently. There is even a HUGE difference between Adobe Photoshop elements and the full blown Adobe Photoshop.
However, the three operations I mentioned earlier, or at least some variation on those operations, were performed to get the final image.
Your sharpening filter achieves a similar output, but gives the image an overall grainy appearance. Whereas daveb's output is soft blocks of color surrounded and/or overlayed by slightly grainy blacks.
Uhhh... sorry for the thread hijack. back to your regularly scheduled forum.