Thread: thumbnail sizes
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  #60  
Old January 13th 18, 11:06 AM posted to rec.photo.digital
Phillip Helbig[_2_]
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Posts: 30
Default thumbnail sizes

In article , "Mayayana"
writes:

Then the only other thing I can think of is that
the cameras are saving at different quality levels
and IM is copying them. Their docs say that's what
it tries to do: Set quality at the same level as it
was saved when possible. You could test it by
setting the quality. That might be a good idea,
anyway. If the camera saved at, say, 90, then
IM is going to save a 90 version of a 90.
You can also just check the quality setting of
the cameras, or the resulting photos. Many viewers
will show the quality level of the last save.


OK. At first glance, it seems that the smaller thumbnail files are from
the camera with higher-quality JPEGs.

If it's local, you may not need to resize at
all. IE (and presumably other browsers) is amazingly
fast and efficient at resizing for display. If you
generate a webpage with:
IMG SRC="D:\bigpic.jpg" WDITH=105 HEIGHT=70
you can very quickly generate a thumbnail sheet
dynamically from full-size images.
Of course you wouldn't want to do it that way
online because it would be slow and your visitors
would need to download the big version.


Right.

In case it's useful, here's the thumbnail extractor
package:
http://www.jsware.net/jsware/scrfiles.php5#jpginf

It could probably run in WINE. You just drop a
folder onto it and all available thumbnails are
extracted. But I wouldn't bee surprised if there's
a Linux tool to do the same thing.


Does this imply that the JPEG files already contain thumbnails?