multisite

Installed and activated the plugin in the network backend network envirroment. I’ve a multisite, using the Multilingual Press Free plugin.
Went to one of the three sites and tried to create a gallery.
Because my WP media is big, I’ve divided it in categories. However, I did not find op option to choose one of my Media categories, I only get an overview of all media.
Did I oversee an option for that? If it is hardcoded to use the WP-Media, then at least it should be possible that the pictures of each album are placed in its own Media ctegory.

I’ve ca. 2000 photos, divided in ca. 45 albums (or galleries…. whatever it is called). Each of them should have it’s own gallery and each gallery has to be presented on it’s owm page?
Is that possible?

And a last question: My photos are already on my webserver, each album in its own directory. Is it really nessesary that all pictures again have to be uploaded? Or is there perhaps an option to let the plugin simply read those directories?

I hope to get answers top let me go on testing the free version. If it al is satisfying, I’m happy to get the Pro, but first I want to be sure the free version works without problems.

https://wordpress.org/plugins/responsive-photo-gallery/