I'm not seeing it.

she's got a face.. on her...

I don't see anything at all there Kaworu. And I certainly don't see a face anywhere other then the one on the front of her head. Someone specifically pointing it out would be nice.

There's nothing mentioned in the artist's title, description, tags or in the comments, either.

Yes, there is something at that corner. Try tilting your screen a bit, you should see it's just a little guy.

Well I tilted it all the way in both directions until the white of Danbooru was dark grey and beyond that until I couldn't even see the screen. I didn't see anything. I guess it must take quite a high contrast monitor.

If you don't feel like tilting your screen around, here is an edit with the levels changed to reveal it. And cropped so Photobucket doesn't delete it.

Ah, it's a little Lain. Thanks.