ese settings).
If you think you'll go back to the original settings,
save the old darks somewhere else instead of discarding them.
</blockquote>

When a dark image is taken a file called <span class="fileName">dark.png</span>
is saved in <span class="fileName">~/allsky/tmp</span>,
then moved to <span class="fileName">~/allsky/darks</span>
with a name like "XX.png", where "XX" is the temperature, for example,
<span class="fileName">21.png</span>.
</p>
<p>
When darks are being <b>subtracted</b>, the software 