I will admit that I would be guessing about what your pictures show here, but the main thing is, there is a leak. Question is where is it leaking. Thru a valve (intake or exhaust) or past the rings correct?

You did the compression test to confirms the leak, now do I leak down test to determine where it's leaking. There is a tool you cab buy to do the leak down test. It uses compressed air to locate the leak and what % is leaking. So if the leak is in the valves, pull the head, if it's the piston rings, pull the engine. If it were me I'd pull engine now. Much easier to work with it out of the car. Pulling the engine with one head out will be very unstable.

Good luck!