How clear cached images with overlay

I have changed the image to be used as an overlay layer for <og:image>, bit still in FB Debugger I see old image.

It is related to all images generated by https://www.przyroda.labaj.com.pl/wp-content/plugins/wonderm00ns-simple-facebook-open-graph-tags/fbimg.php

It looks like these images are being cached. How to clear that cache?

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