The simplest way to disable LPM to load the photos is to actually remove the folders from the LPM, because this is just a view app and removing the directories will also prevent them from being loaded into the application. Secondly, mode the directories with images to a safe place, go back to LPM and delete the photos. It the software asks you to remove them from disk, cancel that and continue with the removal procedure only from the LPM's database.