This image (an animated gif file) is from the Wikimedia Commons. It was featured as the “picture of the day” for March 14, 2006, and has been nominated as one of the finest images on the Wikimedia Commons.
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Wikimedia Commons, Image:Steam_locomotive_work.gif, http://commons.wikimedia.org/wiki/Image:Steam_locomotive_work.gif
Wikimedia Commons, Featured Pictures, http://commons.wikimedia.org/wiki/Commons:Featured_pictures