I don't know the mainstream view, but my view, strongly shaped by
someone here on BAUT (you, maybe??) a few months ago, is that the
light is indeed lensed in such a way as to make the source appear larger.
Prior to my epiphany, I had guessed exactly the opposite: that any
object falling into a black hole would be gravitationally lensed so as to
appear smaller than its distance would suggest it should appear. I was
told this was wrong, for the reason you describe, and after drawing a
couple of diagrams like yours, saw that the lensing should produce a
magnification.

I said in a post within the last few months that my guess was that
light coming from just above the event horizon of a non-rotating black
hole would be lensed to make it appear to be twice as large-- that is,
the size of the photon sphere.

The light bending from the Sun has been observed and measured, not
just predicted by theory, but I've never actually seen it referred to as
magnifying. I think it should be referred to that way.

-- Jeff, in Minneapolis

__________________
http://www.FreeMars.org/jeff/

"I find astronomy very interesting, but I wouldn't if I thought we
were just going to sit here and look." -- "Van Rijn"

"The other planets? Well, they just happen to be there, but the
point of rockets is to explore them!" -- Kai Yeves