A couple of blogs (below) give credit to Matsumoto (author of the Japanese blog):

http://obamapacman.com/2011/10/subtle-differences-of-ios-5-v...

http://usersillusions.com/post/11948201269/apple-has-made-so...

And here is a another site discussing the same images without any attribution.

http://www.ipad2iphone5.com/these-ios-5-changes-are-you-cert...