In article , Jennifer
Murphy wrote:

I scanned a page of preprinted Christmas stationery. The image came in
from the scanner as a jpg file. After some editing, I tried to save it,
also as a jpg. A "JPEG/GIF save options" dialog popped up. I've uploaded
a screen shot he

https://www.dropbox.com/sh/6koey4sos2814we/yoIRm9YAqW

It had two sections. The top section was entitled "JPEG:". Since that's
what I was using, I assume only those options apply. Are any of these
setting wrong?

there is no right or wrong, it depends what you want to do.

for photos that have exif/iptc/xmp etc, you would likely want to
preserve that information, but a scanned image doesn't have that so in
this case, it doesn't matter. if you also edit photos then you probably
will want to preserve that.

don't bother with progressive jpegs and it's almost guaranteed you do
not want a greyscale image, so leave those off.

you could disable chroma subsampling for the highest quality, but it's
not anything humans will be able to see so there's no point. if you
really wanted the highest quality you'd not be using jpeg.

does your scanner software let you safe as tiff or png? jpeg is lossy
and scanning is a pain, so it's best to use a non-lossy format from the
scanner, such as tiff, then convert it to jpeg later. that does take up
more space than jpeg, but disk space is cheap.

The bottom section was entitled "GIF:". Since I was saving as a JPEG, I
assume these don't apply.

the bottom section applies to gif only, and the top section only to
jpeg.

But if I were, can anyone explain what the
Interlaced and Transparent Color options mean and whether I should have
them on or off?

interlaced draws every other line so you see *something* quickly and
then it goes back and fills in the rest.

this was useful when people were stuck with slow modems so they would
see a low quality version in half the time and then they could wait for
the full image if they wanted (or just close the page if they didn't
care). with broadband being ubiquitous, there is no need to bother with
that anymore. gifs are tiny anyway and they appear instantly and
weren't all that slow on modems anyway.

transparent colour is for using a gif on a web page or other image,
where an area can be transparent so other graphic elements can be seen
behind the gif. whatever colour you pick as transparent becomes 'clear'
so you won't see a rectangular block if it doesn't match the page
background.