Left to right and top to bottom these are the images and their artists/owners:

Gandalf the Grey - New Line Cinema
Arwen/Luthien - George Zeil
Merriadoc Brandybuck - New Line Cinema
The Grey Havens - Darrel Sweet
Gollum - Ted Naismith
Peregrin Took - New Line Cinema
Frodo Baggins - John Howe
Boromir - New Line Cinema
Arwen - New Line Cinema
Beren/Aragorn - George Zeil
Gandalf the White - New Line Cinema
Theoden - New Line Cinema
Luthien Tinuviel - Alan Lee
Legolas - New Line Cinema
Peregrin Took - Douglas Beekman
Frodo Baggins - Lord of the Rings Movie Poster from New Line Cinema
Aragorn - Lord of the Rings Movie Poster from New Line Cinema
Elrond - New Line Cinema
Galadriel - Brothers Hildebrant
Gimli - New Line Cinema
Guard of the White Tower - Alan Lee
Bilbo Baggins - New Line Cinema
Sam Gamgee - New Line Cinema
Sauron - John Howe