I saw someone asked this question on a website once, and found it intriguing. The moving image is undoubtedly king in terms of communication and some video clips I will never forget - the planes hitting the Trade Center on 9/11, the Zapruder film, the Hindenburg crashing, MLK's I have a dream speech (although maybe those last 2 are more memorable for the sound than the visual). That said, it could be argued that the still image is just as powerful because it is more memorable, and because it has no sound so it stands or falls on its own. I don't know about you, but I tend to remember things as still images and find them very powerful that way. The fireman covered in dust and blood at ground zero. JFK junior saluting the coffin at his father's funeral. The tank man in Tiananmen Square. Churchill's V for Victory. What visuals, still or moving, are most memorable to you?