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For anybody who has looked at the "Save As..."
features in Paint Shop Pro or any other photo editing software,
it's understood their are a million and one different ways
you can save a graphic image. To me, the pifs, tifs, jifs,
are all nice but to a beginner it can be more than a little
overwhelming to say the least. Last week I talked about
how to cut down on the bandwidth it takes to download your
site. Your choice of image compression has a big part to
play in that battle as well. The two standards that most
people are familiar with are ".gif" and ".jpeg"
(or ".jpg" in some places). Who are these extensions
everybody knows, but nobody can figure out the difference
of? When should you use one, instead of the other? Sit back,
grab your coffee and get ready to be taken back to graphic
file format school.
The ".gif" graphic file extension was developed
by CompuServe for it's online ventures. The three letters,
"GIF" are actually short hand for "graphic
interchange format". Although CompuServe does own the
rights to the name; and that's the reason you see it refereed
to as CompuServe GIF in some programs, that doesn't mean
you have to pay CompuServe any royalties when you save something
under that format. If you want to start getting technical,
you already did that when you purchase your graphic editing
software.
There are plenty of good reasons to use the ".gif"
file format. They are good for simple graphics, logos, animation,
and images you wish to have a transparent background. The
reason ".gif" images lean toward a more simple
aspect of file compression is because they save space by
bumping you down to the choice of only 256 colors. How does
it make up for only using 256 colors? Take a good close
look at a ".gif" image. If you get in close enough
you can see that things really start to get pixilated the
closer you get. In some spots even, you might notice that
you see a bunch of different colored dots in a certain area
that you didn't notice before. This is called "dithering".
The file knows it doesn't have that shade of color, so it
tries it's hardest to recreate the color by shifting around
the dots. This causes the untrained eye to see colors that
in reality aren't represented or supported by the image
itself. Now lets move over to the ".gif's" good
friend, the ".jpeg".
A ".jpeg" (or as we like to say here in the south
a "Jay-Peg") is not owned by a public company
like the ".gif" extension is. The four letters
"JPEG" stand for "Joint Photographic Experts
Group". Just like with the ".gif" though
it does have it's own strengths and weaknesses.
The ".jpeg" files use a different compression
scheme than the ".gif" files do. With ".jpeg"
they remove the data that the human eye can't see to reduce
the file size. These files are still a lot bigger than ".gif"
files are, but they are still better for the web than an
uncompressed image would be. The thing to remember is that
every time you save your file with the ".jpeg"
or ".jpg" file extension, you loose data every
time, because every time it compresses the file more and
more. The ".jpeg" compression method is better
suited for photography, highly detailed artwork, and files
that need to blend from one color to the next very smoothly.
In conclusion, both file formats have their good and bad
sides, and the perfect file extension still does not exist.
The best thing you can do is use each as it was intended
to be used. Also remember to keep multiple backups of the
images you edit so that you may go back to the original
"un-compressed" image and make your changes. Also,
pick a format for an image and stick to it. Switch over
on file formats could reduce the clarity of your image,
and in the long run make for a fuzzy picture for your viewers.
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