Go into the option page of this add-on in Xenforo ACP, disable the master switch for URL screenshots and put "1" into the "Preview Cache Lifetime" field.
This will delete all screenshots after the next daily cron has been run. You can run the cron manually to delete them immediatelly.
This will delete all screenshots after the next daily cron has been run. You can run the cron manually to delete them immediatelly.