Example of Archive Repertory to protect images from download?

I am trying to use the Archive Repertory plugin to protect original images from download, but it doesn’t seem to do anything in that regard.

I have added the required snippet to the root .htaccess file:

# Archive Reperatory plugin redirect rules
Options +FollowSymlinks
RewriteEngine on
RewriteRule ^files/original/(.*)$ https://[site url]/archive-repertory/download/files/original/$1 [NC,L]

In the plugin settings, I have set the file size limit to a very small value, but nothing happens. The file at https://[site url]/files/original/2097572/large_image.png is still accessible.

The plugin instructions make it sound as if editing routes.ini is optional. But is it? I have changed routes.ini to have archiverepertory_download.defaults.mode = "attachment", but still nothing happens.

If anyone has gotten this aspect of the plugin functionality to work, could you give me an example of what you added to .htaccess and routes.ini to make it work? I’m sure I’m doing it incorrectly, but don’t know what I’m missing.