As my graphical skill are virtually zero, I remember having experimented some time ago with exactly the same technique you've described above. Of course my results were not even close to yours but it got me thinking how great it would be to have some automated process of scaling down and "pixel-arting" some hi-res (bitmap or better yet, vector or 3D) graphics. Of course then there would be no art in such pixel-art, would it?
Heh, you can get pretty close:

But you always have that feeling it needs a bit of a touch up.
If you push the res too low anything highres starts looking like shit because the design wasn't optimised for being shrunk down so much - if you turn that pinup to something like 16x32 it's barely even a good silhouette. The sample used is 128x256, upscaled x2 for the record. Took 2min using a trackpad

edit: came back to review, seems imgur raped the progressive pixel perfect jpeg but the png is several meg so just take it as granted that it's not as good as hand pixelling it either way

@egoitzOsa - that's cool, some of the detail is a little jumbled though re: what's arm, what's tail, what's leg.
ed: paged.
Some little practice before returning back at all to
The Wild West
#Hellboy