Need a landscape photo with certain shade of blue, green, yellow, or red but can\’t find one? Here\’s the technology that will make your task easier. Flickr is a web app with flash sketch pad and RGB color picker. You sketch using the built-in sketch pad and pictures that somehow similar to your sketch will be retrieved from Retrievr image index.
Look at these screenshots below. Retrievr is not very accurate yet but is an interesting technology developed for searching photo.
System One: Retrievr