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Shrinking pictures but retaining resolution

Last response: in Computer Peripherals
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Anonymous
December 23, 2004 12:50:30 PM

Archived from groups: alt.comp.periphs.dcameras (More info?)

I have a Sony DSC-P41 digital camera, hooked up to a P4, WinXP SP2
desktop computer. The camera is set to take pics at the 1MP resolution.

When I email pics taken at that resolution (in JPEG format), I usually
shrink the pics somewhat because they are too large to view adequately. I
can do this with a Windows XP powertoy program called "Image Resizer." Or I
can use IrfanView. However, with both programs I've noticed the picture
quality of the now smaller pic is slightly degraded. Not as sharp as the
original. Is there anything that can be done to prevent this, or is this
inevitable with JPEG images?
Anonymous
December 23, 2004 1:32:02 PM

Archived from groups: alt.comp.periphs.dcameras (More info?)

On Thu, 23 Dec 2004 09:50:30 -0500, "History Fan"
<IReALLYHaTESPam@IReallYHATESPAM.com> wrote:

> I have a Sony DSC-P41 digital camera, hooked up to a P4, WinXP SP2
>desktop computer. The camera is set to take pics at the 1MP resolution.
>
> When I email pics taken at that resolution (in JPEG format), I usually
>shrink the pics somewhat because they are too large to view adequately. I
>can do this with a Windows XP powertoy program called "Image Resizer." Or I
>can use IrfanView. However, with both programs I've noticed the picture
>quality of the now smaller pic is slightly degraded. Not as sharp as the
>original. Is there anything that can be done to prevent this, or is this
>inevitable with JPEG images?

No. Shrinking destroys picture information whether jpeg or raw or
bmp or ...

You can use cropping and only send the part that you want them to
see.
Anonymous
December 23, 2004 7:30:57 PM

Archived from groups: alt.comp.periphs.dcameras (More info?)

"History Fan" <IReALLYHaTESPam@IReallYHATESPAM.com> wrote in message
news:YWAyd.92$IZ2.28@fe37.usenetserver.com...
> I have a Sony DSC-P41 digital camera, hooked up to a P4, WinXP SP2
> desktop computer. The camera is set to take pics at the 1MP resolution.
>
> When I email pics taken at that resolution (in JPEG format), I usually
> shrink the pics somewhat because they are too large to view adequately. I
> can do this with a Windows XP powertoy program called "Image Resizer." Or
> I can use IrfanView. However, with both programs I've noticed the picture
> quality of the now smaller pic is slightly degraded. Not as sharp as the
> original. Is there anything that can be done to prevent this, or is this
> inevitable with JPEG images?
>
It is expected for the resized picture to be degraded some.
Maybe apply a little sharping to the resized image.

There are different algorithms for resizing, some are better quality than
others.
In Irfanview the best is Resample (better quality) and use Lanczos (slowest)
filter.

If you start with the best resolution of your camera and then downsample to
a smaller size in steps, the result is a sharper image. I usually take 2
Megapixel images and then downsample to 640 X 480 for the web or email. My
camera is 2 Megapixel max.

--
CSM1
http://www.carlmcmillan.com
--
December 24, 2004 1:36:11 PM

Archived from groups: alt.comp.periphs.dcameras (More info?)

The image resolution in pixels is a separate issue from the size of the
image in inches or cm. (Based upon data encoded in the image file.)
Irfan view does have (last time I checked) the capability to set this
independently of the image pixel count.) Admittedly, display and printing
pixel/dot density will have an effect on the viewed/printed quality of an
image. Emailing images gets into some additional issues, such as limits on
size imposed by the IP and the email programs in use. We routinely attach
such pictures rather than imbedding them to avoid some of the problems.

Due to post exposure image processing in camera, or on a PC, the perceived
quality of a picture may actually be better than a higher resolution image
of the same exposure.


"CSM1" <nomoremail@nomail.com> wrote in message
news:5pCyd.8005$wi2.1282@newssvr11.news.prodigy.com...
>
> "History Fan" <IReALLYHaTESPam@IReallYHATESPAM.com> wrote in message
> news:YWAyd.92$IZ2.28@fe37.usenetserver.com...
>> I have a Sony DSC-P41 digital camera, hooked up to a P4, WinXP SP2
>> desktop computer. The camera is set to take pics at the 1MP resolution.
>>
>> When I email pics taken at that resolution (in JPEG format), I
>> usually shrink the pics somewhat because they are too large to view
>> adequately. I can do this with a Windows XP powertoy program called
>> "Image Resizer." Or I can use IrfanView. However, with both programs
>> I've noticed the picture quality of the now smaller pic is slightly
>> degraded. Not as sharp as the original. Is there anything that can be
>> done to prevent this, or is this inevitable with JPEG images?
>>
> It is expected for the resized picture to be degraded some.
> Maybe apply a little sharping to the resized image.
>
> There are different algorithms for resizing, some are better quality than
> others.
> In Irfanview the best is Resample (better quality) and use Lanczos
> (slowest) filter.
>
> If you start with the best resolution of your camera and then downsample
> to a smaller size in steps, the result is a sharper image. I usually take
> 2 Megapixel images and then downsample to 640 X 480 for the web or email.
> My camera is 2 Megapixel max.
>
> --
> CSM1
> http://www.carlmcmillan.com
> --
>
>


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