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Subject: 
Re: Uploading pics at Brickshelf
Newsgroups: 
lugnet.loc.au
Date: 
Sat, 30 Aug 2003 23:07:55 GMT
Viewed: 
579 times
  
Image size in dots per inch (dpi) need not be more then 72!

Yes, even as a JPG, a file can still be very large. In JPG, there are 3
significant parameters you need to control:

* size (height/width)
* dots per inch
* compression

Some programs are really stupid. If you tell them to reduce the
height/width, they assume you want to retain all the information in the file
and so they achieve this by increasing the dots per inch (or vice versa)
which isn't very helpful if your goal is to reduce the file size.

Personally the best program I have found for dealing with the problem of
coverting dozens of digital photos that are:

* too big as files for download speeds
* too large in size (height/width) to display on a normal screen
* too many dots per inch (unnecessary for most screens)

is Irfanview, which is freeware available at:

http://www.irfanview.com/

While many programs can do the conversion of a single image file, it is
extremely tedious to have to repeat the process many times when you have
lots of photos. There don't seem to be many programs around that can do
batch conversion of many files (e.g. all the photos you just uploaded from
your digital camera). This is where Irfanview is very good -- its batch
processing mode is very good -- you must set up the format, size and DPI you
want and then select the set of files to do it on, and away it goes. You can
set it up to overwrite the original files or put the news ones in another
folder or rename them, etc etc. I found it very easy to use -- just
downloaded it and started using it as it was very intuitive.

About the only thing I found I had to experiment with was the compression
ratio setting for JPG as this is where you are trading-off picture quality
for the size of the file (i.e. "info-loss"). For example, 70% compression
makes a very small file (very quick to download) but the image quality was a
bit too blurry for the kinds of pictures I had, whereas I found 80%
compression made the file a bit bigger but the image quality was more
acceptable. Now I suspect this compression ration versus image quality is
somewhat dependent on the nature of the photos you are taking and what will
be acceptable quality for say photos of sunsets might be different than for
a detailed Lego photo or the wording on a sign etc. So, for this reason, I
would suggest running it a few times using different compressions and see
what combination of file size and image quality best meets your needs.
Irfanview runs quite quickly, so it is no hassle to experiment with
different settings over your set of photos until you are happy with them
(just don't select the option to over-write the originals obviously!).

Irfanview can do lots of other things, but I've never bothered to use those
features so I can't comment on them. But having looked around for quite some
time to find a good, quick and cheap solution to the problem of uploading
large numbers of digital photos onto the Web, I have to say that Infranview
was by far the best of all the programs I downloaded or was shown by friends
etc -- and it's free!

Kerry



Message has 1 Reply:
  Re: Uploading pics at Brickshelf
 
<SNIP> See previous post... Wow there's a free program for batch conversion! Now no one has an excuse not to reduce there file size to atlest a 100dpi image.. I use photoshop, but its alittle pointless telling people to use it (or using it as an (...) (21 years ago, 31-Aug-03, to lugnet.loc.au)

Message is in Reply To:
  Re: Uploading pics at Brickshelf
 
(...) Your problems are here: '1.37mg size. The actual photo sizes are 800 x 600' and in this case (from just what you have said) you have done nothing wrong. Its normal too, 1.3meg should take about 5 mins on a normal non cable (broadband) internet (...) (21 years ago, 30-Aug-03, to lugnet.loc.au)

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