Excellent

Being totally technically inept, I proceeded carefully. The developer warns about irreversible issues that may occur in some circumstances, and gives plenty of advice about how to prevent disasters, so kudos to him. I only wanted to get rid of redundant media, and this plugin did a good job of identifying it. But to be safe, I didn’t delete anything in bulk. I spent a whole day going through my posts and media library and double checking before pressing the delete button. A long-winded process, yes, but I got my result in the end.