Vets Day 9th Marines my Grandpa

This is a picture of my grandpa on Bougainville.  I think he was 18 or 19 here.  They are leaving Torokina point on Bougainville after 48 hours of intense fighting.  The battle of Torokina Point was one of the bloodiest battles the Marines have ever fought in. Pure Hell! This picture has been in hundreds of books and now numerous webpages.  I've always tried to find what government office this picture comes from I would so love to get a copy.  Every search i do i can not find a archive number but yet i still find it everywhere.  If someone can help me that would rule!