Yes, to remove an image from a post:
1) Visit the post on the “Edit Post” screen
2) Open/view the Custom Fields meta box
3) Delete the image URL
That will remove the image from the post itself. Next you want to delete the image from the Media Library:
1) Visit the Media Library
2) Delete the image
Lastly, and optional, to prevent submitted images from being used as Featured Images, you can disable the “Featured Image” option in the plugin settings.
I cannot see a Custom Fields meta box?
Do I need to add this option?
Is this a feature of the Pro version or could my theme be hiding it?
“I cannot see a Custom Fields meta box?”
If you are using Gutenberg Block Editor, click on the three dots in the upper-right corner of the screen, then select options, then enable custom fields meta box.
Or if you are using the Classic Editor, click on the Help tab in the upper-right corner of the screen and check the box to enable the Custom Fields meta box display.
I have done as suggested and can now see the fields. I have deleted the image URL and clicked “Remove Featured Image” but the link still shows on the actual post.
I do not want to delete the actual image from Media as it is used elsewhere.
Any idea why it still appears?
It sounds like something that your theme or another plugin is doing. A quick test for the theme is to temporarily switch to one of the default WP themes and try again. To test other plugins, you can follow this troubleshooting guide (under the “Plugins” section).