I use AMC and just put in head-on shots of the DVD covers
AMC is not that great at getting correct movie covers, even if you change the dvd picture download to hi-res version.
So it can be easier to use the internal my movies database scan to download your movies, select the cover art you want running MP and select imdb, scroll through picture selection until correct.
Then in AMC select these hi-res pictures (ending in L) and save to its amc catalogue, i also save as xml with pictures.
Backup Your Mediaportal moviesdatabase file and Thumbs\movie folder, Also the AMC\catalogs folder (if that's where you have everything saved to).
Hopefully this is a one of process, because everything is backed up.
ps the DVD cover picture totally depends on resolution you are running tv\monitor at, if not a standard widesreen format then picture will not look right in cover.
United Kingdom