They are the idea of Chinese artist Liu Bolin. He gets himself painted by fellow artists (and I mean that he himself IS the 'canvas') in front of rows of products in a supermarket.
Read more about his idea behind this art project, called 'Plasticizer' in an article on Trendhunetr.com.
But this is definitely not the only such a project he has done. No, he has made himself 'invisible' in different places and against all sorts of backgrounds around the world.