Can't really tell, that looks oil-wet not coolant wet. Is there coolant on the bottom of the spark plug (on the electrodes?) that would be the only thing that would indicate a head gasket leak. The electrodes look normal. If it's just oil on the top of the plug there that's just a leaking valve cover gasket, not a big deal.
Coolant in the driveway could be a number of things, water pump weeping is a possibility but so is a cracked or leaking water line.
I've also seen the intake manifold gasket & on another occasion the throttlebody gasket fail, leaking coolant into the intake tract and causing smoke, but was not the head gasket.
A compression test, maybe a leakdown test might help determine what's going on if you can't pinpoint any external leaks