Set art over network

Hello.

I use multiple fileservers, with one acting as a MySQL server for Kodi and it also acts as a Kodi client in my office. I manage a few movie sets in my library, and I have made posters for most of them.
I can set the art manually on the fileserve/MySQLbox just fine, but it doesn’t show up on the livingroom Kodibox and ‘droid Kodi units using the shared library.

I used to be able to set the pathway to the posters with network paths. But it seems this is no longer possible. I can only browse local paths now.

Is it possible to get the set art to show again, without having to keep multiple copies and using local paths?