To see the full image when you visit the flickr page, click on the ‘all sizes’ button and choose the original image size. The text should be readable then.
On closer inspection I’ve just noticed that one of the characters looks a bit like Mickey, the star of the Sendak book. It’s a little difficult to tell, as Mickey spends most of the book stark naked, rather than covered in a large over coat like the one he wears in this adventure. It’s surely some sort of parody though.