Remember, books are free (or almost free, depending on where you live) with your amazing, magical library card.
Lucy Micklethwait books are wonderful. She has numerous art books, but these rhyme and are so cute! My toddler and my 5 year old like them.
My older child LOVES the wordless books by Jacqueline Preiss Weitzman. I think we are definitely going to have to buy these, because we keep checking them out from the library. I love the detailed lists of artwork featured in the back of the books.
Olivia features Jackson Pollock and Edgar Degas paintings inside. Reading this book to my son is when I first realized he recognized art from book to book. Our local museum has a Degas sculpture and its fun to point it out to the kids now that we are familiar with the artist.