For the moment, I only use my HifiBerry for Airplay and internet radio. I want to use an external usb drive or NAS, but I remember that HifiBerry OS downloads or saves the album covers as jpg or png in the specific folders. I don't want that. I'm very secure in correct the ID3-tags of my MP3's and with keeping the folders neat, without unnecessary files (like nfo, m3u, ... ). I don't find the setting to avoid this behaviour.
Also, for that reason I don't want HifiBerry OS not to change anything in the tags. Can I be sure of that?