Metadata listview

How do I control the look of the Icon displayed in “list View” ?
Have structured movies and have a .jpg viewd as cover - but the other icon and the pic from the movie displayed in other views all come from the movie - and takes time to generate. Id like to have my own .jpg’s displayed - can I do that ?
Have tried to place a pic called “moviename”-fanart.jpg but that is never displayed ??