2d engraving

Hi,

I hope to use a raster-to-vector conversion sw to convert photos to
gcode for 2d engraving. I have tried wintopo but the face of the
subject was not recognisable.

For example I tried to convert Marilyn Monroe picture to vector
diagram

http:\\hometown.aol.com/tuzahu973/marilyn.html

but the face came out not recognisable.

Is wintopo suitable for application like this or are there other
suitable software?

thanks

peter

BTW how about competing to see who can produce the best vector
diagram/gcode of the above?