image_writer.c has code originating from vf_screenshot.c, vo_jpeg.c, and
potentially others. vo_image.c is based on a bunch of those VOs as well,
and the intention was to replace them with a single codebase.
vo_tga.c was written by someone who was not or not could be contacted,
but it doesn't matter anyway, as no code from that initial patch was
used.
One rather old patch (57f77bb41a) reordered by libjpeg patch API calls,
and the author of the patch was not contacted. But at least with the
smoothing_factor override removed, this pretty much exactly corresponds
to the official libjpeg API example (and might even reflect a change to
those - didn't dig deeper). This removes the -jpeg-smooth option. While
we're at it, remove all the other dropped jpeg options from the manpage
(which was forgotten in past changes).
078b275514