Two decades ago, in 1996, I prepared a small website telling the story of the above woodcut and tracing its first appearance to Camille Flammarion in 1888. That old website remains available, largely unchanged: "This is not a medieval woodcut." It explores the image as visual rhetoric, concluding that its enduring appeal lies not so much in the flat Earth myth but as an icon of our common quest of discovery and exploration, the challenge of "boldly going where no one has gone before." Many colorized versions of the woodcut appear on that site in low resolution, with permission and according to fair use.
However, wouldn't it be great if there were a colorized version available in higher resolution which educators and anyone could freely use? This is why my daughter, Susanna J. Magruder, created the colorized version of Flammarion's woodcut shown above, which she is distributing in the public domain. Enjoy! You can put it on your website, a t-shirt, a coffee mug, or print out a copy on quality paper for your wall.
I've already taken advantage of Susanna's work by using her version as the icon for my spring 2014 course, "History of Science from Antiquity to the Age of Newton," which is available on OU's Janux digital course platform. To me, this woodcut is the ideal icon for the course, and I used it before for the same purpose. If you're interested in the longer story of the shape of the Earth, here is a 45-minute video I made some years ago that features the woodcut.