I'm in favor of including the last picture as part of the article, because it shows the possible world we gain by averting existential risk. I don't believe that "context" is necessary, the image is self-explanatory.

Nitpicking on ringworld vs. stanford torus is not relevant, or interesting. The overall connotations and message are clear.

"Sci-fi" of today becomes "reality" of tomorrow. Non-transhumanists ought to open up their eyes to the potential of the light cone, and introducing them to that potential, whether directly or indirectly, is one of the biggest tasks that we have. Otherwise people are just stuck with what they see right in front of their eyes.

For a big picture issue like existential risk, it fits that one would want to also introduce a vague sketch of the possibilities of the big picture future.

Suggesting that the Earth picture itself doesn't belong in the post shows some kind of general bias against visuals, or something. You think that a picture about saving human life on earth isn't appropriately paired with a picture of the Earth? What image could be more appropriate than that?