Series poster not showing

[Betelgeuse]

When I chose Series in Mediabrowser only about 50% show the corresponding art for the serie.
If I chose Folders and chose my Series folder, only 2 out of 64 folders shows the folder art.
I use Media Companion for scraping movies/series, and it creates nfo files and art compatible with Xbmc.
How does Serviio chose which art to show? Is it from the nfo file or image files located in the directory?

[zip]

In Series view it uses the metadata (although I think it only works for online sources currently).
For Folders category it just uses thumbnail of a random file in the folder.

[Betelgeuse]

I think the poster handling is something should be worked on. It is very convenient and nice looking to have the right file/series poster showing. The "folder picture overlay" that shows on top of posters as it do now is a great feature. It differs folders and files clearly.