User blog comment:Ḡwẵine Ḹٍٍkƨ Ĺiĸe Ͼềлȑềd/Wallpaper/@comment-180964-20120425000607/@comment-180964-20120426202023

Not sure off the top of my head but I'll look into it. If I had to take a guess right now I think it was around time just before Series 4 officially started an I think they also came out around the same time as the Episode Press Release as well.