Yaroslav M. Blanter wrote:
I am sorry to say, now I see quite an opposite attitude: "You have put a picture under a free licence, now do not complain". This is fine of course but does not encourage the authors very much.
I think this is one of the best advantages of the French image printing initiative (Wikiposter), that it makes it absolutely clear to everybody that images uploaded to Wikipedia (to the Wikimedia Commons) are allowed for commercial reuse. There is no better way to explain this, than to print and sell the images. This is indeed an innovation in education. My congratulations!