another little thing to notice, the little white dingy in the top pic, not in the 2nd or the tird but in the last :- Could be very coinsadentle but I think the probility of that is extremaly low. Cosidering everything else in the first and last pic are the same.
EDIT: ANOTHER thing, now this can't be coinsadence but the cars as well, exactly like the boat, picture 1 and 4 have the same cars on them, where as 2 and 3 don't :D" Dam i feel clever :) :D (Y)
EDIT AGAIN: Also note the cone at the bottom left corner on pictures 2 and 3 and next to it the upside down boat, its not there in picture 4 :D