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From: Tim on 5 Apr 2010 20:49
Elmo wrote:
> On Sun, 04 Apr 2010 12:27:26 -0700, Paul Furman wrote:
>
>>> - Set "JPEG/GIF save options" to "Set file size = 100KB (RIOT
>>> Plugin)"
>>
>> I'm not sure this makes sense for most cases, jpeg file size will
>> vary depending how much detail.
>
> Actually, that's the beauty of this setting.
>
> No matter what the JPEG size is, it will set it to 100KB (or whatever
> you choose). It's magic.

Which is exactly why it makes no sense at all. An image that is sharp and
contains a lot of fine detail will be over-compressed and could potentially
be ruined by forcing a file size on it.

--
Tim


From: Tim on 5 Apr 2010 21:02
Elmo wrote:

> Assumption: You want to automatically rotate, shrink to 100KB, set to
> 72dpi, strip out the EXIF data, and rename the new emailable files
> based on the EXIF date & EXIF gps coordinates for all photographs in
> a Windows folder.

Why are you setting the resolution to 72 pixels per inch? If they are to be
emailed and viewed on screen the resolution doesn't matter at all, if they
are to be printed then 72 ppi is way too low.
Despite the common misconception, on screen images don't need to have a
resolution of 72 ppi. The only thing that effects its size and quality on
screen is its size in pixels. The size can be changed if it's incorporated
into a web page by a scaling factor, but it's best to make a copy that is
the correct size (in pixels) to start with, and in either case resolution is
irrelevant. For on screen images, the resolution only comes in to play when
the image is displayed in a page based format, like Word or a desktop
publishing program, where the software makes an inaccurate attempt to show
the virtual piece of paper at the same physical size as it is in the real
world.

--
Tim


From: Elmo on 5 Apr 2010 21:57
On Tue, 6 Apr 2010 10:49:22 +1000, Tim wrote:

> Which is exactly why it makes no sense at all. An image that is sharp and
> contains a lot of fine detail will be over-compressed and could potentially
> be ruined by forcing a file size on it.

I understand your point but I don't understand the mathematics. Apparently
this Irfanview feature uses something called a "RIOT Plugin".

Googling, I find RIOT stands for the "Radical Image Optimization Tool".
http://criosweb.ro/software/RIOT.dll

It looks like GIMP also utilizes the RIOT (http://luci.criosweb.ro/riot)
Radical Image Optimiation Tool (http://registry.gimp.org/node/20778).

I wish there were a Wikeipedia on this RIOT Radical Image Optimization
Tool; but none yet.

So, I guess, the real question, is how well does the RIOT Radical Image
Optimization Tool work in Irfanview batch mode. (works well enough for me)

From: Elmo on 5 Apr 2010 22:07
On Tue, 6 Apr 2010 11:02:22 +1000, Tim wrote:

>> Assumption: You want to automatically rotate, shrink to 100KB, set to
>> 72dpi, strip out the EXIF data, and rename the new emailable files
> Why are you setting the resolution to 72 pixels per inch? If they are to be
> emailed and viewed on screen the resolution doesn't matter at all

Good question!

I thought reducing the DPI from whatever it is from the camera down to 72
DPI lowered the file size (in bytes on disk).

Can you clarify the relationship of DPI with bytes on disk?

Assuming two photographs are exactly the same, except one is 72 DPI and the
other is, say, 1,200 DPI, wouldn't one would be vastly larger in file size
(bytes on disk) than the other?

If the answer is Yes, then that's why I recommend 72DPI for emailed photos.
If the answer is No, then ... you're right ... it's a waste of time to set
the DPI in Irfanview Batch Mode.

What is the right answer to recommend to batch shrink common photos to be
emailed?
From: Ray Fischer on 5 Apr 2010 22:42
Tim <timmorr64(a)XremoveXhotmail.com> wrote:
>Elmo wrote:

>> Assumption: You want to automatically rotate, shrink to 100KB, set to
>> 72dpi, strip out the EXIF data, and rename the new emailable files
>> based on the EXIF date & EXIF gps coordinates for all photographs in
>> a Windows folder.
>
>Why are you setting the resolution to 72 pixels per inch? If they are to be
>emailed and viewed on screen the resolution doesn't matter at all, if they
>are to be printed then 72 ppi is way too low.

Does _anything_ pay attention to the DPI setting?

--
Ray Fischer
rfischer(a)sonic.net

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