I have some albums (natively mounted) network shares and external hard drives. it works. But when they also show up, when they are disconnected. I added them as album on a network share and album on external hard drive respectively. The network shares folders in /media/username/sharename are completely empty. The hard drive's mount directory doesn't exist, until the hard drive is mounted. Thumbnails show up, too. But of course, I cannot open the pictures. Is this meant to be like this? I am not sure.
Yes it's a feature, which had long been requested by other wishes here. You can access all images of your collection, search them, view the thumbnails, apply rating (in the database) etc. Of course, you cannot open the picture and you cannot edit the file's metadata (*) (*) even this could be implemented by a sort of delayed writing