The illustrations in The Wonderful Wizard of Oz have a very creepy, old, unique feel. The artist who illustrated this book was W.W Denslow. He was L. Frank Baum's collaborator and friend, he also co-held the copyright. Baum was the author of The Wizard of Oz. His drawings in this book are engaging and they not only provide a visual of the story but they are a narrative themselves.
Denslow was an editorial cartoonist, and is well known for his illustrations in The Wonderful Wizard of Oz, he also loved doing caricatures.
His drawings in the Oz books have odd, muted colors to them. Not all of his drawings in the book have color, but the ones that do give off an eerie vibe. I love how he draws, he definitely found his technique and it ties together with the story of The Wizard of Oz. The illustrations are so creepy which makes them fascinating. He has great line work and his compositions are wonderful.