In total, Flickr now hosts over 100 million CC-licensed images, so even the least restrictive CC license accounts for a total of 12 million photos, and, of course, even the most restrictive CC license still allows for free sharing of the images, as long as the image is not changed and the author is attributed.
Flickr now holds the world's largest repository of Creative Commons-licensed images, but according to a new study, most Flickr users opt to license their images under the most restrictive CC license.