a mask and use that as input to
<b>pamcomp</b>.

<P>The output image is always of the same dimensions as the underlying
image.  <B>pamcomp</B> uses only parts of the overlay image that fit
within the underlying image.

<P>To specify where on the underlying image to place the overlay
image, use the <B>-align</B>, <B>-valign</B>, <B>-xoff</B>, and
<B>-yoff</B> options.  Without these options, the default horizontal
position is flush left and the default vertical position is flush top.

<p>The overlay image, i