Great Egret?

[SmartWombat]

Some illustrations I see the green by the eye, some not.
And there's a white morph reddish egret photo I've seen that has the green.
So, experts, how do I know what I'm looking at.
Is it the bill colour ?
Yellow - Great Egret
Black tip - Reddish Egret but white
I found it hard to assess the size of the birds on my first encounter.

[Canon_Bob]

Yup - Great Egret

[SARtech]

Agree. You can tell also if the legs are black. (or close to black)