vel of quality of the JPEG files (final and intermediates
if asked to be written). The value can go from 0 to 100 with a
default at 95.</dd>
<dt><code>--nocrop</code></dt>
<dd>Keep the full size of input images. By default images are cropped
to the area that is valid for all images in the input stack, to
avoid distortion near the edges.</dd>
</dl>


<h3 id="Image-alignment-options">Image alignment options</h3>

<dl>
<dt>
<code>--reference</code>=index</dt>
<dd>Select image index (starting from 0) to use as 