Congrats on teaching your dog to read! I'm still working on that trick myself. The cats seem to have a headstart, though, apparently recognizing the fronts of treat packages, for example...

Purely anecdotally, I once heard, with regard to "art" created via the use of rubber stamps, that if one takes an existing image, but changes it by at least 15% (and how that would be calculated I am not certain), it is considered for copyright purposes a new work. I'm afraid I do not have a citation, but from your description, I'd say you far exceeded the requisite 15%.

FWIW, I do not think anyone would meaningfully object to such a small slice of book cover being shown. YMMV, however.

(BTW, I believe you mean to say homenode, as opposed to Personal Nodelet. ;-))

HTH,