>Gerard,
>
>I know that GDI+ has some dificulties working with some PixelFormats.
>Maybe for this specific case, you can convert your GIF to BMP, resize it, ans SAVEASGIF.
>
>This should work.
>
>If you want, send me the piece of code you are using to do it, and the properties of the GIF you are trying to manipulate.
>
>Does it happen with all GIFs ? Or just some ?
>
>Regards
>cesar

I have try to save to bmp to disk and reloading to no luck, same error on resizing.

But, I have found a workaround:
img.ToClipBoard()
img.FromClipBoard()

This round trip to and from the clipboard convert the image to Bitmap (quickly in memory) and it can be resized without error after that.

Thank for the bmp tip even if it dont have worked directly, this drive me in the right direction.

Thank again :)