Re: Could this be the cause of my problem?
Hard to tell in the pictures --- > I would check the head over good and if you do not see anything wrong get it magnafluxed and checked for flatness --- check the block with the pistons all the way down with good light for cracks.
Then if nothing is found, I would change the gaskets and torque everything down and give her a try
If this is your long time boat ----- sounds like a plan.
If not and the head bolts were loose ----> smells fishy to me --> like someone has already been in there and found something they didn't like
Best of luck
OFM