Hey Bob,
I suggested you use Image Cleanupwordpress plugin
Find [URLnf="https://wordpress.org/plugins/image-cleanup/"]here[/URLnf]
The main function of the Image Cleanup
Its main job is to support you to delete all the images that not used in your posts
How to use
When finished installing the plugin, you go to Tools -> Image Cleanup to use it.
Here you will see it displayed as follows:
View attachment 773
View attachment 774
As pictures above, Press check boxes to select more pictures. Better way, try clicking on the Home button so that it performs scanning Images for the last time to have exact statistics.
A detailed list of image is not used will show up
If you want to delete it all, just press select all and choose Delete tool in the Bulk Actions and the Apply button is pressed. If you have more images then you will need to do on many pages for each page it only display 100 items.
If you do not want to delete, you can choose File Move option to take it to a different folder to manage.
Hopefully it helps, you will no longer worry about cleaning up not used images anymore.