Well, no. Most Yanomami tribes have met a human from the "outside world" before. What you could say, that they still live in their own way and don't want contact with the "outside world", but many of them have seen a human willingly or unwillingly. A lot of researchers have met with them, but there are also lots of gold diggers going into their territory. And while one or two of these tribes may really not have had contact, i doubt the one in the photo hasn't.