This has been asked in a few place including, reddit, chiebukuro, mal, 4chan, and a couple IRC channels. But it seems that the best result is just some people recalling they have seen it somewhere before.
I tried to reverse image search it but google gave me nothing.
Perhaps if the image was broken up by panel that would yield further results? Cause the images do not look like they belong on the same page but were put together for some purpose (probably to show off expressions or how cute the character is.)