Protecting images not working

Logging-in using Patreon and locking Posts for patrons only works fine. The only thing that doesn’t work is patron-locking images.

And no, locking from a Post or the Media page still doesn’t work.

I’ve also noticed that if you used a Featured Image as your thumbnail, you can delete some of the URL to view the full image, even when the whole post is locked.
For example, you have a locked image artwork.png that you’ve also used as a Featured Image in an also locked post. It’s automatically generated thumbnail is artwork-250×250.png. By viewing the source, people can just delete the -250x-250 part and see the whole artwork.png.

For now, I’ll only be using this plugin to allow my patrons to log-in, and allow them to hide ads depending on their pledge.