What really is the correct posture?

[daredd]

I am really confused about what the correct posture is
I've seen 2 videos on my fyp (didnt watch them and can't find them now) about how the conventional 'good posture' actually isn't the right posture and just saw a guide thread posted here but I am not really sure what's the truth.

help

 

[Xotus]

back straight shoulders down head up to neutral

 

[Glazey]

I am really confused about what the correct posture is
I've seen 2 videos on my fyp (didnt watch them and can't find them now) about how the conventional 'good posture' actually isn't the right posture and just saw a guide thread posted here but I am not really sure what's the truth.

help