c binary function to samples in two images

<DT><B><a href="pamsummcol.html">pamsummcol</a>      </B>
<DD>summarize (sum, average, etc) an image by column

<DT><B><a href="pnmcat.html">pnmcat</a>        </B>
<DD>concatenate images

<DT><B><a href="pnmpad.html">pnmpad</a>        </B>
<DD>add borders to an image

<DT><B><a href="pamcomp.html">pamcomp</a>       </B>
<DD>create composite (overlay) of images

<DT><B><a href="pnmcomp.html">pnmcomp</a>       </B>
<DD>obsolete version of <b><a href="pamcomp.html">p