David J Taylor added these comments in the current discussion du
jour ...

JPEG is a lossy form of saving the picture -

The Bayer sensor is already lossy, having only one of RGGB at
any of four pixel locations, so one could make the argument
that JPEG imposes no further loss.

However, JPEG imposes an additional loss, because of the
approximations it makes. You can control the degree of
approximation by the quality setting on cameras, or by the
compression or quality settings in your software.

Here we go again! David, you and I get along OK. You're level
headed and not any kind of elitist, while at the same time, you
have an excellent foundation in the theory of all of this. I think
the OP is a pretty rank novice and has probably gone unconscious by
now in this thread. You have such a great way to express your ideas
in words that people of all technical levels can understand that I
bet you can do far better than my feeble attempt at helping the OP.

--
HP, aka Jerry