EmuMovies has content that differs from ours (though some images aren't a LOT different). We typically say to download everything you want from LaunchBox first, then use EmuMovies to fill any gaps you have in your collection. If on the current version this becomes even easier with the Media Limit being set since it will grab LaunchBox stuff first, THEN EmuMovies. If you have "Remove Rough Image Match" on we also scan images as you get them to see if they are the same image (but in a different file) and attempt to remove those copies as well to help with any potential duplicate image issues.