Hi,

I've found quite a lot of messages and posts by developers at a loss
as to how to use MakeTransparent() to generate a GIF89 image with a
transparent color...but I've come across a particular problem that
I've yet to see mentioned, namely that using

bitmap.Save("filename.gif")

works just fine (correctly sets the transparent color in the GIF
file), whereas

bitmap.Save("filename.gif", ImageFormat.Gif);

doesn't work - the "transparent" color is consistently turned to
black.
Similarly for the Save(Stream, ImageFormat) overload, which is the one
I actually wanted to use (as I'd like to create the GIF file in
memory).  Only workaround is to use the first form, saving to a temp
file, then load the file into memory.

I've also tried the other overloads for Bitmap.Save() with no luck.
Wondering if "ImageFormat.Gif" implies GIF87...but there is no
ImageFormat.Gif89.

Dylan