Michael Herring created a somewhat macabre painting for the cover of the Del Rey edition of Speedy in Oz. Of course, that's not too difficult when one of the main characters is a living dinosaur skeleton! Here we see Terrybubble the dinosaur floating through the air, with Speedy and Gureeda tucked inside his rib cage.
I also have a preliminary sketch for this piece. The image is basically identical, except that the dinosaur bones are brown rather than white - probably a truer depiction, but the white bones do brighten things up a bit! The background hills have also grown, against a more dramatic sky.
John R. Neill also drew this incident as a chapter title. His Terrybubble looks a bit more flexible, but Speedy and Gureeda are difficult to distinguish.
This is the last of the Herring paintings I have. He painted one more, for The Wishing Horse of Oz, but the Del Rey series ended at that point. I've heard rumors of possible sketches for further titles, but I've had no luck in finding whether these exist.