With Hadfield returning to Earth today I'll miss his fantastic
paintings err I mean photos of the Earth.
Now, supposing that this one here was a real photo, in FET what are we looking at here?

It appear we see the Earth's curvature, which can't be the edge of the "spotlight" obviously. Nor can it be the edge of the Earth's disc, or at least not as it's generally understood, since the Sun shown here is beyond the edge, shining through the atmosphere, and as we all know in FET the Sun is always somewhere above the Earth's disc. So it's pretty confusing from the FET standpoint.
Can anyone point me to or produce a sketch that shows how this would work, because I can't figure it out.