The follow pictures are of me (two featuring my wife, Lauryn). I edited all three using filters and color tools in GIMP.

For the above picture, I used the Hue-Saturation tool to isolate red and magenta tones only, and the Softglow tool to add a glow to the edges.

I added GIMP's Cartoon filter to this picture of us.

In this picture, I used the Hue-Saturation tool to increase the saturation on all colors, and I increased the contrast of the picture.