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by R. Prasad, Ottawa,
Canada
In the example below, I outline a fairly common and basic batch process most
people can use - downsizing a whole directory of image files so that they can
be posted to the web for your friends and family to enjoy online. Whether you
get your images out of a digital camera, or like me, you still like to shoot on
35mm film, and like to order a photo-CD along with your prints, you will
generally start with a directory full of high-resolution images. High
resolution also means large file size. Today's megapixel digital cameras offer
astounding clarity and image resolutions - its common place to have images that
are upwards of 1600 x 1200 pixels in size when you download them from the
digital camera, or open up the photo-CD from the developer. These are great for
printing or examining in detail, but they are impractical for posting on the
web. The larger the image size, the longer it takes to upload the image to a
web server, the longer it will take for people to download it to see it in your
browser, and the quicker it will take for you to hit your website's storage
and/or bandwidth usage limit. With web images, smaller is generally better -
you want people to see what you saw quickly and conveniently. If they want more
details, tell them to invite you over for a barbeque and show them the images
in person - remember, socializing with real people can be a good thing
sometimes.
For instance, the photo below, as it originally came on my photo-CD, had a
resolution of 1536 X 1024 pixels, and has a file size of just over 1 Megabyte.
That's great if you have the huge file sitting on a CD-ROM or on your hard
drive already, but imagine viewing it online - even with a DSL connection, it
would take about 20 seconds to download to your browser (don't even ask if you
just have a 56K dialup connection), and the actual image would probably be
larger than the common 1024 X 768 pixel screen size (or less) on most PCs - you
would have to scroll around to see the picture in parts.
 This
photo was taken with a disposable 35mm camera, and shows a cable car going up a
mountainside during my trip to Europe. I downsized the image to a more
web-friendly 384 x 256 pixels, and it takes up a mere 25Kb of disk space.
That's about 1/ 40th the file size of the original digital image. You can still
see the cable car globes, the trees, the city of Grenoble in the valley below,
and the Chartreuse mountains in the background. The image is big enough that
you get the idea of what I saw on my trip, and you aren't going to be waiting
ages for the image to download, even on a dial-up connection. Another
interesting thing about this image is that it is still very clear - there are
no edge artefacts or distortions from downsizing it. Anyone who has used the
basic photo editor program in Office or some other image tools will appreciate
this - some programs use algorithms that drop, distort, or smear pixels
together in order to recompress (i.e. shrink) an image - MagicViewer doesn't
mess with the bits anymore than it has to.
So you can see an example of why we might want to edit an existing image file -
we'd like to make it a smaller and more suitable for web posting. Now what if I
have a whole directory full of fat image files that need to be downsized for
the web? To manually resize each of these images would take about a minute or
two each for an experienced (and patient) user. If you have a directory with
many files - there are 24 photos per roll on my camera - this adds up to a lot
of hours doing the same activity in front of the PC. This is where
MagicViewer's "Batch Processing" function makes a tedious and complicated job
very quick and painless. Ok, lets get to how...
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