>pamscale</b>, possibly smoothing or
blurring the result with <b>pnmsmooth</b> or <b>pnmconvol</b>.  Or use
the special case program <b>pbmtopgm</b>.

<p>To dither a color image (to reduce the number of pixel colors),
use <b>ppmdither</b>.

<A NAME="lbAE">&nbsp;</A>
<H2>OPTIONS</H2>

<P>The default quantization method is boustrophedonic Floyd-Steinberg
error diffusion (<B>-floyd</B> or <B>-fs</B>).

<p>Also available are simple thresholding (<B>-threshold</B>); Bayer's
ordered dither (<B>-dither8</B>) with 