you click the START button on windows &/8, then enter "cmd" into the box at the bottom.
you then run the convert. i had a movie in my videos directory called frozen.mp4
to convert the movie i typed
cd \users\sean\videos
ffmpeg -i frozen.mp4 -s 50x50 f-%d.jpg
now i select the first frame, "f-1.jpg", using the pictures effect