Ok, when adding stuff to the library you are using the Kodi smb client which access the files without mounting them as a drive. If you really have an interest to have it mounted as a drive you would need to do so manually via fstab.
But there is no need to do so, you just could do it all within Kodi. If you want to change e.g. the location for the thumbnail checkout example 2 of path substitution.
http://kodi.wiki/view/Path_substitution
1 Like