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Newbie: JPG puzzle?

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March 16, 2005 12:04:12 PM

Archived from groups: rec.photo.digital (More info?)

Is there any way I can keeep jpg file at the same size?

This is any 170K jpg. All I did was to have flipped it horizontally
.. It then saved as a 340K file at 100%.

I thought, for flipping, the software only re-arranged the pixels.
What can i do if I want to keep jpg at small size?

does it mean only the original JPG is the smallest?

ABC
Do not reply by email. Replay to NG

More about : newbie jpg puzzle

March 16, 2005 12:04:13 PM

Archived from groups: rec.photo.digital (More info?)

ABC wrote:

> Is there any way I can keeep jpg file at the same size?
>
> This is any 170K jpg. All I did was to have flipped it horizontally
> . It then saved as a 340K file at 100%.
>
> I thought, for flipping, the software only re-arranged the pixels.
> What can i do if I want to keep jpg at small size?
>
> does it mean only the original JPG is the smallest?
>
> ABC
> Do not reply by email. Replay to NG


100% is a bit excessive. 95% is fine.

If it's not been cropped, you can rotate without any change using
irfanview or most any newer program.
Anonymous
March 16, 2005 12:04:13 PM

Archived from groups: rec.photo.digital (More info?)

On Wed, 16 Mar 2005 09:04:12 +0800, in rec.photo.digital ABC
<ABC@nospam.net> wrote:

>Is there any way I can keeep jpg file at the same size?
>
>This is any 170K jpg. All I did was to have flipped it horizontally
>. It then saved as a 340K file at 100%.
>
>I thought, for flipping, the software only re-arranged the pixels.
>What can i do if I want to keep jpg at small size?
>
>does it mean only the original JPG is the smallest?

There are lossless rotation tools available.
http://sylvana.net/jpegcrop/losslessapps.html
----------
Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
See images taken with my CP-990/5700 & D70 at
http://edwardgruf.com/Digital_Photography/General/index...
Related resources
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Anonymous
March 16, 2005 12:04:13 PM

Archived from groups: rec.photo.digital (More info?)

ABC <ABC@nospam.net> writes:

> Is there any way I can keeep jpg file at the same size?
>
> This is any 170K jpg. All I did was to have flipped it horizontally
> . It then saved as a 340K file at 100%.
>
> I thought, for flipping, the software only re-arranged the pixels.
> What can i do if I want to keep jpg at small size?

What software did you use, and what exact command? Ordinary
photo-editing software doesn't support the lossless rotation
capabilities mostly; that's mostly supported in viewing and organizing
software (like Irfan View and Thumbs Plus). If you do use the
lossless rotation commands, the file size changes *very* little (I
don't understand why it changes *at all*, but in my experience it
does; but only very little, like 1% or something).

I *think* what you did was opened the file in a photo-editor, flipped
it, and then re-saved at top jpeg quality. I suspect the file
*wasn't* at top jpeg quality originally, and that explains the
increase in size.

> does it mean only the original JPG is the smallest?

Nothing too magical about the original.
--
David Dyer-Bennet, <mailto:D d-b@dd-b.net>, <http://www.dd-b.net/dd-b/&gt;
RKBA: <http://noguns-nomoney.com/&gt; <http://www.dd-b.net/carry/&gt;
Pics: <http://dd-b.lighthunters.net/&gt; <http://www.dd-b.net/dd-b/SnapshotAlbum/&gt;
Dragaera/Steven Brust: <http://dragaera.info/&gt;
Anonymous
March 16, 2005 1:03:11 PM

Archived from groups: rec.photo.digital (More info?)

ABC wrote:
> On Tue, 15 Mar 2005 19:53:00 -0600, David Dyer-Bennet <dd-b@dd-b.net>
> wrote:
>
> >What software did you use, and what exact command? Ordinary
> >photo-editing software doesn't support the lossless rotation
> >capabilities mostly; that's mostly supported in viewing and
organizing
> >software (like Irfan View and Thumbs Plus). If you do use the
> >lossless rotation commands, the file size changes *very* little (I
> >don't understand why it changes *at all*, but in my experience it
> >does; but only very little, like 1% or something).
> >
> I tried both in Irfanview and Photoimpact. Once you rotate the image
> and save, it will be bigger, much bigger.
>
> ABC
>
> Please do not reply by email.Reply to NG


As a previous poster had already mentioned: you have to use "lossless
transformations -> rotate" in Irfanview.
This will save the rotated picture automatically at (almost) the same
size.

Markus
Anonymous
March 16, 2005 3:45:13 PM

Archived from groups: rec.photo.digital (More info?)

>>If you do use the
>>lossless rotation commands, the file size changes *very* little (I
>>don't understand why it changes *at all*, but in my experience it
>>does; but only very little, like 1% or something).

When you do lossless rotation, the encoded image will normally be the same
size as the original, but there's more than that in a jpg file.

There's also a great deal of header information containing camera settings,
maybe a thumbnail image, and other stuff. The software writing a jpg has a
great deal of flexibility when it comes to the format of this header
information. The reason the file size changes is that the saving software
probably uses a different header layout (even though it saves the same
information) from whatever saved the original (probably a camera).

In my experience, cameras tend to use inefficient header layouts. I presume
the firmware writers were prepared to sacrifice a few bytes of file size to
keep the firmware simple. That's legitimate because they probably have to
fit their code into a limited amount of memory.

With my own home-made photo application I can open an image from my camera
and save it again without re-encoding (ie. no quality loss) and almost
invariably end up with a smaller file than the camera managed (and yes, my
software can also do lossless rotation).

Keith
(free PhotoMan download from
http://homepages.tesco.net/~Keith.Sheppard/photoman/hom...)
Anonymous
March 16, 2005 9:32:04 PM

Archived from groups: rec.photo.digital (More info?)

ABC <ABC@nospam.net> writes:

> On Tue, 15 Mar 2005 19:53:00 -0600, David Dyer-Bennet <dd-b@dd-b.net>
> wrote:
>
>>What software did you use, and what exact command? Ordinary
>>photo-editing software doesn't support the lossless rotation
>>capabilities mostly; that's mostly supported in viewing and organizing
>>software (like Irfan View and Thumbs Plus). If you do use the
>>lossless rotation commands, the file size changes *very* little (I
>>don't understand why it changes *at all*, but in my experience it
>>does; but only very little, like 1% or something).
>>
> I tried both in Irfanview and Photoimpact. Once you rotate the image
> and save, it will be bigger, much bigger.

I just grabbed random image, checked its size (43.9k), viewed it in
Irfanview, selected "jpg lossless operations" and then 90 degrees
clockwise, let it run, closed the file. Checked the file size
(unchanged), and viewed the file again, and I'm viewing the rotated
version.

I believe your mistake is in viewing the image, and then saving it.
The lossless jpeg plugin in irfanview modifies the file directly; when
you save after that, you're re-compressing, which introduces new
artifacts and may depending on the compression setting change the file
size as well.
--
David Dyer-Bennet, <mailto:D d-b@dd-b.net>, <http://www.dd-b.net/dd-b/&gt;
RKBA: <http://noguns-nomoney.com/&gt; <http://www.dd-b.net/carry/&gt;
Pics: <http://dd-b.lighthunters.net/&gt; <http://www.dd-b.net/dd-b/SnapshotAlbum/&gt;
Dragaera/Steven Brust: <http://dragaera.info/&gt;
Anonymous
March 16, 2005 9:33:32 PM

Archived from groups: rec.photo.digital (More info?)

davem@cs.ubc.ca (Dave Martindale) writes:

> David Dyer-Bennet <dd-b@dd-b.net> writes:
>
>>What software did you use, and what exact command? Ordinary
>>photo-editing software doesn't support the lossless rotation
>>capabilities mostly; that's mostly supported in viewing and organizing
>>software (like Irfan View and Thumbs Plus). If you do use the
>>lossless rotation commands, the file size changes *very* little (I
>>don't understand why it changes *at all*, but in my experience it
>>does; but only very little, like 1% or something).
>
> That's probably because lossless JPEG rotation is not just moving DCT
> coefficients around. It has to undo the (lossless) Huffmann compression,
> then move the DCT coefficients around, then re-do the Huffmann
> compression. No information is lost, but you *are* re-encoding the
> data using Huffmann in a different order which can give a slightly
> different compressed size. You might also be doing 2-pass Huffmann after
> the rotation while the camera only did 1-pass Huffmann.

Thanks, never looked at the spec details myself. So that makes sense
then.
--
David Dyer-Bennet, <mailto:D d-b@dd-b.net>, <http://www.dd-b.net/dd-b/&gt;
RKBA: <http://noguns-nomoney.com/&gt; <http://www.dd-b.net/carry/&gt;
Pics: <http://dd-b.lighthunters.net/&gt; <http://www.dd-b.net/dd-b/SnapshotAlbum/&gt;
Dragaera/Steven Brust: <http://dragaera.info/&gt;
Anonymous
March 16, 2005 11:47:04 PM

Archived from groups: rec.photo.digital (More info?)

David Dyer-Bennet <dd-b@dd-b.net> writes:

>What software did you use, and what exact command? Ordinary
>photo-editing software doesn't support the lossless rotation
>capabilities mostly; that's mostly supported in viewing and organizing
>software (like Irfan View and Thumbs Plus). If you do use the
>lossless rotation commands, the file size changes *very* little (I
>don't understand why it changes *at all*, but in my experience it
>does; but only very little, like 1% or something).

That's probably because lossless JPEG rotation is not just moving DCT
coefficients around. It has to undo the (lossless) Huffmann compression,
then move the DCT coefficients around, then re-do the Huffmann
compression. No information is lost, but you *are* re-encoding the
data using Huffmann in a different order which can give a slightly
different compressed size. You might also be doing 2-pass Huffmann after
the rotation while the camera only did 1-pass Huffmann.

Dave
March 17, 2005 1:28:51 AM

Archived from groups: rec.photo.digital (More info?)

On Tue, 15 Mar 2005 17:26:12 -0800, paul <paul@not.net> wrote:


>100% is a bit excessive. 95% is fine.
>
>If it's not been cropped, you can rotate without any change using
>irfanview or most any newer program.

I am using Irfanview!
Open any JPG. flip it and click 'save'. It will open a dialog box
suggesting 85% quality. Set it to 100% and I end up with a bigger
file.

ABC

Please do not reply by email.Reply to NG
Anonymous
March 17, 2005 1:28:52 AM

Archived from groups: rec.photo.digital (More info?)

On Wed, 16 Mar 2005 22:28:51 +0800, in rec.photo.digital ABC
<ABC@nospam.net> wrote:

>On Tue, 15 Mar 2005 17:26:12 -0800, paul <paul@not.net> wrote:
>
>
>>100% is a bit excessive. 95% is fine.
>>
>>If it's not been cropped, you can rotate without any change using
>>irfanview or most any newer program.
>
>I am using Irfanview!
>Open any JPG. flip it and click 'save'. It will open a dialog box
>suggesting 85% quality. Set it to 100% and I end up with a bigger
>file.

Use the lossless transformations. Make sure you have the plugins
installed first. Then choose Options => JPG Lossless Operations.
________________________________________________________
Ed Ruf Lifetime AMA# 344007 (Usenet@EdwardG.Ruf.com)
See images taken with my CP-990/5700 & D70 at
http://EdwardGRuf.com
March 17, 2005 1:30:33 AM

Archived from groups: rec.photo.digital (More info?)

On Tue, 15 Mar 2005 19:53:00 -0600, David Dyer-Bennet <dd-b@dd-b.net>
wrote:

>What software did you use, and what exact command? Ordinary
>photo-editing software doesn't support the lossless rotation
>capabilities mostly; that's mostly supported in viewing and organizing
>software (like Irfan View and Thumbs Plus). If you do use the
>lossless rotation commands, the file size changes *very* little (I
>don't understand why it changes *at all*, but in my experience it
>does; but only very little, like 1% or something).
>
I tried both in Irfanview and Photoimpact. Once you rotate the image
and save, it will be bigger, much bigger.

ABC

Please do not reply by email.Reply to NG
Anonymous
March 17, 2005 1:30:34 AM

Archived from groups: rec.photo.digital (More info?)

On Wed, 16 Mar 2005 22:30:33 +0800, ABC <ABC@nospam.net> wrote:

>On Tue, 15 Mar 2005 19:53:00 -0600, David Dyer-Bennet <dd-b@dd-b.net>
>wrote:
>
>>What software did you use, and what exact command? Ordinary
>>photo-editing software doesn't support the lossless rotation
>>capabilities mostly; that's mostly supported in viewing and organizing
>>software (like Irfan View and Thumbs Plus). If you do use the
>>lossless rotation commands, the file size changes *very* little (I
>>don't understand why it changes *at all*, but in my experience it
>>does; but only very little, like 1% or something).
>>
>I tried both in Irfanview and Photoimpact. Once you rotate the image
>and save, it will be bigger, much bigger.
>
>ABC

Do a little experimentation.
You're saving at 100%. Try lower values, and see what the file size
is, and if there's any degradation that you will notice.

--
Bill Funk
Change "g" to "a"
March 17, 2005 12:15:04 PM

Archived from groups: rec.photo.digital (More info?)

On Wed, 16 Mar 2005 18:32:04 -0600, David Dyer-Bennet <dd-b@dd-b.net>
wrotd:

>I just grabbed random image, checked its size (43.9k), viewed it in
>Irfanview, selected "jpg lossless operations" and then 90 degrees
>clockwise, let it run, closed the file. Checked the file size
>(unchanged), and viewed the file again, and I'm viewing the rotated
>version.
Got that.

This is better Photimpact( and I bet PS,too). Photoimpact does not
offer lossless and same-file-size rotation. Why?



ABC
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