I did this using Vectric PhotoVCarve. The idea fascinated me and they really are quite wild to see up close and personal. My original photo is not great, but I like the result.
I did this in two passes. The roughing pass was done with a 1/8" ball nose mill, with a 40% stepover. The finishing pass was done with a 1/16" ball nose, with a 10% step over. The finishing pass took almost 4 hours! The piece is roughly 5" x 5".