Sub Test()
Dim pal As New StructPaletteOptions
Dim flt As ExportFilter
pal.NumColors = 32
pal.PaletteType = cdrPaletteOptimized
pal.Smoothing = 50
Set flt = ActiveDocument.ExportBitmap("C:\Temp\img.gif", cdrGIF, , cdrPalettedImage, PaletteOptions:=pal)
flt.Finish
End Sub