Hmm what's up with this puzzling image tiling result?

 mk 2016

mk 2016

So this is annoying. The last few tiling runs I've attempted have all come out looking like this. <img src="http://oikosjournal.files.wordpress.com/2011/05/solved-smiley-face1.jpg">

I tried tiling post capture but no luck! Wonder what I'm missing... Guess I could cut it up in PS and put it together again. I do like puzzles!

I wonder how people did this before image software did it for you or allowed you to move the pieces around easily?