Simplify the following text for a Grade 10 native English-speaking person.
Original: Photographer Annie Leibovitz took pictures of Knut that were used for an environmental campaign , including Vanity Fair magazine 's May 2007 Green Issue in which he was superimposed into a photograph with American actor Leonardo DiCaprio .
Simplified: Photographer Annie Leibovitz took pictures of Knut that were used for an environmental campaign .