"J. P. Gilliver (John)" wrote

| What I meant was: once an image has been reduced to 256 colours, then
| any editing _that did not change the number of colours_ (such as
| brightness or _possibly_ contrast tweaking) would not result in further
| corruption if saved as GIF; once it's been reduced to 256 colours, then
| anything further you do to it, _provided it doesn't result in an
| increase in the number of colours_, can still be saves as GIF without
| further degradation.

I guess that's true. It works when doing things
like diagrams. But I find that anything more
complex, even a screenshot, really needs to be
kicked back up to 24-bit color if I want to work
on it. For instance, brightening a screenshot.
That will need more than 256 colors to do. So
I have to revert back to 24-bit and then
resave it later.

| I find it kind of ironic when this topic comes up.
| I don't think I've ever heard you say this, but whenever
| I talk about conserving space on disk, many people
| will respond with, "Ah, that's not worth the trouble.
| Disks are so cheap these days!" Yet when it comes
|
| No, you'll rarely hear me say that, as I come from the bygone era (my
| first computer had 1K of memory; before that, the first one I worked on
| had 16 memory locations). I will _sometimes_ concede that view when
| discussion of time versus resources comes up, but given the choice and
| time, I'll go for saving space where practicable. (Actually, more in MP3
| files than images; my eyesight, touch wood, has not deteriorated with
| age other than the ability to close-focus, but my hearing _has_ lost
| top, and/or I haven't had speakers capable of great top for some time.)
|

I wish I could switch with you. I don't listen to
music in general and usually keep the audio turned off on
my computer, but my eyesight is getting worse. I
recently mounted my monitor on a drawer slide because
I was leaning forward so much it was hurting my neck.
now I just sit down and pull the monitor toward me...
So I can't lean forward. Though I'm not sure what
the radiation from that close display might be doing to
my eyes.

| When you say they want "vacation photos to fit on disk", do you mean "to
| fit on _a_ disc", i. e. to make a CD (or, I guess these days, a DVD), to
| give to friends/relatives?

No I just meant that a lot of people are constantly
taking 10MB phone shots and then want to save them
on their computer. The people who complain that they
need to buy a 4 TB hard disk because the 2 TB is full.
They don't edit. They don't cull their collection. They
also don't resize the images for better storage. They
don't really get the system. They just think of it as
"photos" that came from their phone and went onto their
hard disk. It's like the people who invite you for dinner
and have a 7' high bookcase full of photo albums.
("These 3 albums are little Ricky's christening. Wait'll
you see! And it was so cheap at the drugstore to
get all the shots printed!")

For someone like that, who's not familar with file
formats and doesn't edit photos, a BMP would just
be a JPG that's very big. They wouldn't see the
point.

| (I remember using a Sony camera at work, that had a floppy drive built
| in - and you could get several pictures on, of acceptable quality! [That
| camera also had something I've never seen before or since: the ability
| to use ambient light to backlight the display.])

Wow. 1.44 MB? They must have been small images.
But I suppose they were also 256 colors?