I wouldn't waste time messing around with the jukebox images.
Follow
this convention for posters and fanart (background) images and you should get good results.
Alternatively you could populate the following tags in the nfo file:
<?xml version="1.0" encoding="UTF-8"?>
<movie>
<thumb></thumb> <!-- url of poster image. use URL formatting, such as http:// for internet resources or file:// for local resources -->
<fanart></fanart> <!-- url of fanart image. use URL formatting, such as http:// for internet resources or file:// for local resources -->
</movie>
Using a meta-data manager such as YaNFOe or
Media Companion (my personal favourite) should assist in assuring the desired images for the type-A personality...