The Ken Burns effect is a special effect used in documentaries when you only have a static photograph of an interesting item. To add some movement and life to the photograph, you zoom into the photo and pan towards a point of interest. It's named the Ken Burns effect because it was used a lot by a documentary film maker named Ken Burns.
You can achieve the Ken Burns effect using CSS animations. It's not even particularly difficult. Just create a div with overflow:hidden to hold the image, then change the image's CSS transform property. Or if you want to be totally retro and backwards-compatible, you could also achieve the effect by changing the image's top, left, width and height using a JS setInterval.