My scanner (an HP LaserJet 3380 all-in-one) is attached to my Windows XP machine. Here is how I obtain half-way decent scanned figures into PostScript format (which I need for a variety of reasons):
pnmtops image005.png > image005.epsNote: Saving as eps in gimp gives bad results. There are also many, many other ways to get bad results (blurry, noisy PS images). There are probably ways to get better results as well. Please send me email if you know!