cale for an image, from 256 lines each containing a
single value.  The values are expected to be in the range 0 to 1, and
are clipped to these limits if not.  For 8-bit images, Gri multiplies
these values by 255, and uses this list for the grayscale mapping.  Such
a list is created by `<font color="#82140F"><code>write image grayscale</code></font>'.
<p>
As an example, consider the code fragment (see <a href="Images.html#Images">Images</a>).
<p>
<TABLE SUMMARY="Example" BORDER="0" BGCOLOR="#efefef" WIDTH="1