This illustration comes from Linda Medley, the comics artist best known for Castle Waiting and a long-time fan of the Oz books. It’s one of five greeting cards featuring Oz characters that she just offered on Etsy. The others show Scraps, Jack Pumpkinhead, the Wizard, and Glinda.
Medley has also created a print of Ozma, the Wizard, and Dorothy (and Toto, too). Her picture of Dorothy is an enthusiastic little girl, notably younger than Ozma and ready for adventure.