Resizing photos, quality

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richardfangnail@excite.com - 25 Nov 2005 02:20 GMT

If you simply resize jpgs to make them smaller, would you see a
difference in quality between using Paint and MS-Photo It, and
Photoshop?

(In Paint you would use Stretch/Skew)

>From what I've seen, I think the quality goes down in Paint.

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Shawn Hirn - 26 Nov 2005 14:00 GMT

> If you simply resize jpgs to make them smaller, would you see a
> difference in quality between using Paint and MS-Photo It, and
> Photoshop?

That depends on how you resize the photos. In PS, if you increase the
image size without resampling, you should get a better printed image.
That being said, if you start out with a poor quality image, you will
end up with a poor quality image if all you do is resize it down.
Resizing will not help improve an image if all you do is view it on your
screen.

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Rolf Buchner [MSFT] - 28 Nov 2005 19:57 GMT

Hello,

When resizing an image to be smaller, the resulting differences between
programs should be negligible, assuming that you save them with the same
compression ratio. Since jpeg is a lossy format, if you choose to save a
file with a high amount of compression there is the chance that artifcats
will be left behind and the image will not look as good.

You can change the compression in the Digital Image Suite Editor as
follows:

1) Click File
2) Click "Save As"
3) Select "JPEG Interchange Format" in the "Save as type" drop-down box
4) Click "Options"
5) In the dialog that appears you can move the slider to the right to
increase quality or left to decrease quality

Note that increasing quality will cause the file to take up more space
on your hard drive.

Thanks,
Rolf

This posting is provided "AS IS" with no warranties, and confers no rights.
Use of included script samples are subject to the terms specified at
http://www.microsoft.com/info/cpyright.htm

> > If you simply resize jpgs to make them smaller, would you see a
> > difference in quality between using Paint and MS-Photo It, and
[quoted text clipped - 6 lines]
> Resizing will not help improve an image if all you do is view it on your
> screen.

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info@scrammit.com - 29 Nov 2005 14:37 GMT

> If you simply resize jpgs to make them smaller, would you see a
> difference in quality between using Paint and MS-Photo It, and
[quoted text clipped - 3 lines]
>
> >From what I've seen, I think the quality goes down in Paint.

Those take too many steps to resize an image - if thats all you are
wanting to do. Try PictureGirdle. Its a free little utility that
works great for resizing. It does batch processing too. If you're
interested its at http://www.scrammit.com/software.htm

HTH

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Paul J Gans - 29 Nov 2005 17:10 GMT

In rec.photo.digital info@scrammit.com wrote:

>> If you simply resize jpgs to make them smaller, would you see a
>> difference in quality between using Paint and MS-Photo It, and
[quoted text clipped - 3 lines]
>>
>> >From what I've seen, I think the quality goes down in Paint.

>Those take too many steps to resize an image - if thats all you are
>wanting to do. Try PictureGirdle. Its a free little utility that
>works great for resizing. It does batch processing too. If you're
>interested its at http://www.scrammit.com/software.htm

Resizing a photo is a bit of an art. Downsizing and upsizing
are very different.

In downsizing you are getting rid of information since there
will be fewer pixels in the final image. NO computer algorithm
can decide exactly which bits of information make the least
difference.

That said, there are some clever algorithms out there. The
only way to find out is to collect several (Irfanview has several)
and try them. What works best on one image might not work
best on others.

Upsizing is far worse. Now the program has to "create" information
since there will be more pixels in the final image than in the
original.

In fact there is absolutely no way to do this. There can't be
more information in the upsized image than in the original. What
various programs do is cheat in different ways. They use what
information is there to guess at what can be created.

Again, the best advice is to collect a few such programs and try
them. And again, different images might expand better using
different programs.

One last thing: no manipulated image will ever contain more
information than the original. This is why many folks advocate
shooting either RAW images or ones with the least jpg compression.
But in practice, downsizing seems usually to lead to better
results than upsizing. So again, shoot the largest images
you can and downsize, rather than smaller ones and upsize.

In the end, only you can judge the results on your images.

----- Paul J. Gans

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