The puzzle has been solved in 35 minutes! Winning transaction here:
https://www.blocktrail.com/BTC/tx/3ddae3ff1e9e0a77e54c0dc2e1ef6bec308d2b999f8cc1a17c643ef0a4453807?txinIdx=0

The solution to the puzzle was a QR code, solving the puzzle works as follows. Each grid of four squares has a number, this number indicates the amount of black squares in that 2x2 grid. You can use this information to color squares black and solve the puzzle.