I doubt that Picasso said "Every child is an artist. The problem is how to remain an artist when we grow up," first because a little googling reveals no source

I doubt that Picasso said "Every child is an artist. The problem is how to remain an artist when we grow up," first because a little googling reveals no source for it (other than the usual spam sites), second because this is a popular post-1960s belief about children (the kind of thing Picasso's generation was unlikely to say, but that later generations would eagerly attribute to $arbitrary_great_artist), and third because from what little I know about Picasso's ego it seems unlikely that he would distribute the status of artist so equitably. So I think this quote should be put in the category of bullshit-till-proven-authentic. It would be fitting if it were bullshit, since it motivates an argument that all anyone had to do in 1907 was decide to paint a few whores and they'd end up with this: http://en.wikipedia.org/wiki/Les_Demoiselles_d%27Avignon http://en.wikipedia.org/wiki/Les_Demoiselles_d%27Avignon.