A couple of suggestions regarding transparent GIFs.  If they're standard
knowledge, my apologies.

1.  When preparing your artwork in Photoshop and while still in RGB
mode, fill your background layer with the colour you will eventually be
using on your webpage (eg. white in your case, Virginia).  If you're
using blurred drop shadows they will blend into the background more
seamlessly this way.

2.  When moving to the Indexed colour mode do NOT use the dither option
(ie. set dither to "none").  The "Pattern" and "Diffusion" settings tend
to creae the effect you said you were getting - more than one shade of
white where you thought there was only one.

3.  I don't use the GIF89a export option to save my GIF, but "Save As"
and then use a plug-in called "PhotoGIF Lite" by Boxtop Software which
allows you to choose which colour you want to make transparent in a
zoomable window which makes it easier to see whether or not you've
achieved the effect you were after before you move to your browser.

Hope this is helpful.

...Brett Clifton

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