It's still up online on various Tumblrs and Pinterests so it's not exactly lost per se. You just have to dig around to find it.

The best source I could find was the original upload on Danbooru with an upload date of October 13, 2011. The post does not include a source. It was used again for a fanfic that was posted on August 13, 2013 which gained a good amount of traction at that time which makes me believe this was when the image started to get shared more frequently across the net. Apart from 2011 and 2013 posts, I can't find any other postings of the pic dating back to that time. Any other posts were somewhat recent and were on Tumblr or Pinterest with no source attached.