Naming Convention to add artwork to "Extras" and "multi-part" movies?

[Oracle 85]

I've done this manually, but want it to be set up in the file system instead. Possible?

Screenshot

[GrimReaper 4739]

Just use one of the accepted naming conventions, i.e. <extrasfilename>-landscape.ext or <extrasfilename>-thumb.ext. 

https://support.emby.media/support/solutions/articles/44001159102-movie-naming