In this image where would the antumbra be?:
There is no antumbra in this image.
An antumbra only exists when the moon is further from the Earth than in that image, so that the moon appears smaller in the sky than the sun.
In that case, when the moon is perfectly aligned with sun, a ring of sun is visible behind the moon. The region in which the ring is visible is called the antumbra.
In the image, the moon is closer to the Earth, so when the moon and sun are aligned, the moon entirely blocks out the sun, and so there is a region of umbra.
That image shows a total eclipse. An antumbra is present only in an annular eclipse.