Well, how does it feel to be a cheater? I bet you are the kind of person who used to use 'God' modes in classic shoot 'em up games.... just like me.
Well, it's all in a good cause, so I forgive you...just this once.
The 3 hidden images are accessible from:
1) The 'More' button on the technical information page. Just to give you an easy start.
2) From the very first image, if you use the 'back' button- after all, what could possibly come before number 1?
3) By clicking on the psychedelic image number 17 from Canada- after all, I did wonder what the original looked like!
OK, that's it, folks.