Re: .jpg viewer for IIGS

[Scott.Alfter@skunkworks.genesplicer.org (Scott Alfter)]

gberigan@cse.unl.edu (Greg Berigan) wrote:
GB>Converting a JPEG to a GIF format is a strange thing to do.  You will
GB>lose color quality in the conversion.  Converting the other way you will
GB>lose image detail.  Also, GIFs will be larger than JPEGs, but as said
GB>you lose quality for the higher compression.  JPEGs can be made without
GB>loss, but then they end up larger than the same image as a GIF would.

Given raw 24-bit image data, JPEG would be much preferred to GIF.  At
sufficiently high (say, 90%) quality levels, you're not likely to notice any
degradation in a JPEG image.  Taking an image with thousands of colors,
though, and distilling it down to a maximum of 256 results, I think, in much
more loss than you'll get by sacrificing a couple of fine details.

If you really want to see where JPEG pulls ahead of GIF, try making "index"
images of dozens of pictures, and then saving them in both formats.  Even if
the source images were GIFs, the resulting JPEG file will look much
better--the posterization that you're likely to see in the resulting GIF would
be objectionable to most people.

The only problem I can see with JPEG is that it's more computationally
intensive than GIF.

Scott Alfter
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