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From: twegner@mwunix.mitre.org (Timothy Wegner)
Newsgroups: alt.graphics.pixutils,comp.graphics
Subject: Re: Compressing GIF images
Keywords: GIF images compress
Message-ID: <twegner.647272507@mwunix.mitre.org>
Date: 6 Jul 90 13:55:07 GMT
References: <127225@csb8.encore.com>
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ddisimo@encore.com (Darrin DiSimo) writes:

>    I was wondering if anyone knows of a PD compression
>program for GIF files.  Gif files are taking up a lot of disk
>space and I know regular compression does not work.

GIF files already use LZW compression, which is why ARC, ZIP etc. 
don't have much if any effect (they all use basically the same method).
What we need is a better method. Obviously there is room for improvement.
For example, a GIF image of a Mandelbrot set should be compressible 50%
just by making use of the symmetry of the image with respect to the X axis.
LZW compression doesn't pick that up.