(YouTube Link)
The only known video images of Holocaust victim and diarist Anne Frank have been circulating YouTube. Lisa Gutierrez writes in the Kansas City Star:
The 21-second, black-and-white video, filmed on July 22, 1941 about a year before Anne and her family went into hiding, shows the front of an Amsterdam apartment building where Anne and her family lived.
Nine seconds into the film you can see a brief glimpse of Anne, age 13, leaning out of a second-floor window trying to catch a glimpse of her next-door-neighbor who just got married.
The authenticity of this film has been verified by the Anne Frank Museum.
http://www.kansascity.com/stargazing/story/1486550.html via Ace of Spades HQ
They already showed this footage in the Anne Frank Remembered documentary that came out in 1995.
The movie was shot before she went into hiding.
http://www.youtube.com/watch?v=4hvtXuO5GzU
Yes, YouTube shows you a video version, but referring to the medium in question as "the only known ..." clearly references the original, which would be film. (Again, using the comparison above, if someone had found a painting of Anne Frank, it would not be referred to as the "only known photograph" simply because it appears on Flickr.)
Yes, it may be pedantic, but in writing, it's often necessary to be so in order to be clear.