If your head gasket was blown, you'd be getting coolant in the cylinders and the engine would have started running rough.
If it's been overheating, it could be a head gasket, it could also be a thermostat.
Have you been losing coolant in the system?
As it stands, for me those photos are too dark to show anything, if you can get photos in daylight it sure would help a lot.
Also, which engine is that?
EJ22
EJ25 SOHC
EJ25 DOHC