I too would like more info on this topic; currently I use the tedious method of finding the image online & saving it as folder.jpg.
I would really like an automated system other than my movies,
I tried my movies twice -first time I just did not like the way it looked & behaved.
Around 9 months after that, after many more positives about it on here, with many people seemingly claiming that sunlight was being generated out of it, I tried it a second time.
It really mucked up all my stored DVD's & took many hours over several nights to clear up. Most annoying I suddenly had multiple copies of the Ali G movie as the thumb nail, despite never having borrowed rented or even watched it.
My movies is going nowhere near any of my hard drives ever again.
I have noticed that Vista media centre does actually download an image as per the DVD in its drive (that is about 95% of the time).
I asume it must be somewhere in the temp folder, does any one know where this file is stored so that I can harvest it?
-It would save my many trips to Lovefilm or Amazon!