Why is there a nuclear mushroom cloud over Earth in this display of the Chinese lunar rover?

Last week, China landed an unmanned spacecraft on the moon. It became the third country to do so, after the United States and the former Soviet Union, and the first in nearly 40 years.

The spacecraft was carrying a lunar rover named Yutu (Jade Rabbit), which will spend the next three months driving around the moon collecting geological data.

That's cool. But there's one big question being left unanswered:

What is up with this nuclear mushroom cloud?

The above photo was taken on Nov. 5, 2013 at the China International Industry Fair in Shanghai. It shows a model of the Yutu rover against the background of Earth. No big deal, except there's a nuclear mushroom cloud bursting from the Earth's surface.

Having trouble seeing it?

Enhance.

(Getty Images)

Huh.

Turns out it's a stock image called "Nuclear Explosion on Earth from Space," which you can download here, where it's described as "a nice wallpaper" for your computer desktop.

How did "Nuclear Explosion on Earth from Space" end up being the "nice wallpaper" behind the Yutu rover model at the China International Industry Fair?

Unknown.

A minor screw-up, or a warning?