This is the best image of the Small Dark Spot that was obtained by Voyager. The small spot is thought to be a storm in Neptune's atmosphere, perhaps similar to the Great Red Spot on Jupiter.
NASA/JPL
<a rel="nofollow" class="external free" href="https://pds.jpl.nasa.gov/planets/images/full/neptune/storm.jpg">https://pds.jpl.nasa.gov/planets/images/full/neptune/storm.jpg</a>