I did go and find a Google pdf of AiW. It's pretty obvious to me that Google has done postprocessing on the text. All of the letters are a true black and fully formed.
The book I looked at has at least a few line drawings which are much more like signatures to any software Google might use. I'd be much more impressed if you found an example of multiple pixelation in one of the drawings.
ML/NJ
Sure, no problem.
This is the book I used, which was the first result when I searched for "Alice's Adventures in Wonderland."
The screenshot I posted came from page 29 of the PDF file. I picked that page because of the proximity of the image to the text, but you can see the same effect on other pages. Just download the PDF and see for yourself. Zooming in, you'll see the same "multiple pixilation" you identified in the scan of Obama's long-form birth certificate.
Moreover, the very first line of the poem shows an example of repeated text pixels, in this case the three O's. This, too, has been called "proof" of forgery. In fact, it's an observable effect of an enhanced PDF scan.