Fórum do Blu Ray
Cyberlink specifically removed the screenshot feature from PowerDVD Ultra version 8 for Blu-ray, so I can only assume there has been some pressure from the BDA or other vested parties to discourage screenshot taking. I would not be surprised if Arcsoft were under similar pressure. All of the open solutions require a "Step 0" which is probably the source of most of the hesitancy around posting specific methods. I will say that none of the open solutions work with copy-protected material and leave the details and extrapolation of that as an exercise for the sly reader.
With that being said, I personally prefer to dump many pre-generated bitmaps and sort through the results with a nice image browser, rather than trying to locate and frame step to specific shots while watching the movie (which can be troublesome with BD-Java navigation restrictions). My current method uses mplayer to dump all the I-frames of a movie file. These occur between 1-2 per second, so doing this typically results in 7000-10000 image files to sort through at a total cost of approximately 10-15GB of disc space.