1) Typically people get their character images from scans. There are a number of good resource sites to get scans. After that it just requires extraction, some cleaning up, and then you're set.
I've seen people draw (both on paper and on the computer), CG, and then wall their drawn characters although this isn't done nearly as much as the getting your image from a scan.
2) If you want to get a character image from a video, more often than not, you're going to have to take a snapshot of the character in the pose that you want them in and then vector the image, due to the difference in resolution size between video and desktop.