Using the Canon Zoombrowser software if you open the MOV video file and start to play it you will see a button called Save As Still Image which will save out the JPG image of the movie at that point. This gives a better result than just trying a screen capture as it will use the frame from within the MOV file. You can also move the movie frame by frame to get the best pose or avoid unwanted blurring from movement. Shooting at a faster frame rate would reduce movement anyway but my video was shot in low light at 1/30 sec.
I would recommend saving at the highest quality setting which strangely isn't the default within the software.
