That's a big fish, you can normally look at their eyes in relation to the body. I used to be a spearo, and this was the way we would judge how large a fish was in clear water. The smaller the eyes, the larger a fish (obviously not talking about 10kg puppies). As the skull growns the eye sockets become larger as the eye it self doesn't really grown in relation to a Gt's head, you can see it very well on that 65kg Gt.
Have a look at my 'normal' photo as my avatar. I am 1,87cm, with the fish on my knees and resting on my chest at an angle. Look at my fingers too, from this you can guess the size.
I do agree how ever photos can be missleading, but each to their own. But why do we fish at the end of the day? It's not to impress a group of people on-line in a virtual world, but it's for that rush when a fish strikes at the surface and you connect. That smile on your face, the sweat running down your face and your reel screaming
