this picture is known as "Casper" or "the visitor". it's origins are unknown but some people claim that it was first presented by Whitley Strieber. according to ufologie.net site the picture was shown to Strieber and he recognized it as something he had seen before in one of his supposed encounters. the site also states, it's possible that the photo is computer generated.
this photo is on the cover of Whitley Striebers book called "communion" and is a drawing or depiction.