Can't turn off longdesc img attribute

Excellent plugin!
But just one thing I don’t understand …

Whenever I add an image now, it always has a longdesc attribute and return anchor, like this ..

<img class="alignright size-full wp-image-100" alt=""
src="https://[MY-DOMAIN]/wp-content/uploads/2014/04/[IMAGE-NAME].jpg"
width="160" height="160"
longdesc="https://[MY-DOMAIN]?longdesc=100&referrer=113" />
<a id="longdesc-return-100"></a>

I cannot see how to turn off this unwanted behaviour.

Most of my images are small and purely ornamental. None of them have title, alt text, description or caption — because they are not needed.

I’m grateful for the opportunity to add an appropriate longdesc, but right now all images have a link to an empty description, unless I edit the image tag manually.

Have I done something wrong? Have I missed an obvious instruction (very possible – my vision is deteriorating week by week).

Cheers ??

https://www.ads-software.com/plugins/wp-accessibility/