Some movie's not showing thumbnail

WD TV Live SMP, latest firmware.   If I do a meta-data content search, it pulls the correct movie info, backdrops, etc. But it refuses to associate the movie poster to the file. 

Any clues?

See if the following link helps. 

http://community.wd.com/t5/WD-TV-Live-Streaming/Movie-Thumbnails-missing/m-p/419834/highlight/true#M9519