Denslow and Oz

WW Denslow's illustrations for L. Frank Baum’s The Wonderful Wizard of Oz have become regarded as the definitive images for the story, at least until the movie came along much later. According to the Public Domain Review:

"Denslow worked closely with Baum to create pictures of characters and landscapes not described in the text. He was truly a co-creator. As Denslow said, he had to “work out and invent characters, costumes, and a multitude of other details for which there is no data — and there never can be in original fairy tales."

Because he shared the copyright with the author, he became a wealthy man. He bought an island, built a castle on it, and declared himself 'King Denslow I.' But alcohol and bad investments brought his empire to an unfortunate end.
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Read more online: "W. W. Denslow’s Illustrations for the Wonderful Wizard of Oz (1900)"at the Public Domain Review