Well, that won't work for me (no directshow, I'm on Debian). But I already tought of 2 solutions: use mplayer with -vo png and import the images with gimp-gap; or watch normally with '-vf-pre screenshot' and hold the 's' key when I see the scene I want. I'm going to test them later, when I get some time.
Hey. i saw your post in the Code Geass avatar thread and didnt want to take it off track. You can use a program called VirtualDub to capture moving frames as gifs, then import the gifs to a program like imageready.