One of my reservations in switching to Linux was Photoshop. I really like Photoshop and I’m comfortable with it. In order to get comfortable with GIMP, I decided to do a few little projects. One of the filters that I really missed from photoshop was anisotropic filtering, but I found a wonderful filter for GIMP called Greycstoration.
I took the original files, erased the background, touched them up, and converted them to greyscale. Then I created multiple layers with varying degrees of threshold applied. Then I used the sobel difference of gausians to add some edge highlights. I adjusted the opacity on the layers to achieve the posterize effect, and then used the greycstoration filter to smooth everything out. Here are the results with the originals.