I have one entity which besides other information holds many images. This is one 2 many. In situation where I need to load just first from that collection to slow loading I have following query which retrieve collection of images.
 List<Entity> data = session.Query<Entity>()
          .Fetch(x=>x.Photos)//here I need only first element
          .Fetch(x=>x.Features)
          .ToList();
 
     
     
    