Since there's no decent built-in color quantization for the .Net gif
encoder (really, who in the heck uses the web-safe palette anymore?),
we have to do it ourselves.

This page:

http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dnaspp/html/col
orquant.asp

provides the code to do it, but since it involves unsafe code, you
cannot use pure VB.Net to pull it off - the VB.Net must call compiled
C# code.

My real question is, why in the heck, even in .Net 2.0, is there no
built-in color quantization for the gif encoder that does something
like the Octree-based quantization?  Seriously, saving simple gif image
should be nowhere near this painful, especially after all these years
of people having to rewrite the Octree code.