The image was originally drawn by Hergé to commemorate the first moon landing, Apollo XI, and had a speech bubble of Tintin saying "Bienvenue sur la lune Mr. Armstrong!" (Welcome to the moon, Mr. Armstrong!).
Apparently Hergé presented this drawing to the astronaut Neil Armstrong. According to what Michael Farr has said in the past the two men regularly corresponded with each other for a number of years. Neil Armstrong is known to be a very private person and has rarely spoken in public about the Apollo 11 mission.
The image was also re-produced for the
Ils ont Marché sur la lune exhibition, which was held in Paris in 1985. The speech balloon, with the "Mr. Armstrong", was removed.
Coincidently, [shameless self promotion here!] I just listed the book of the exhibition on eBay. Should anyone like to take a punt, please feel free!
Moderator Note: See thread about the Armstrong image
here.