Dim myImageCodecInfo As ImageCodecInfo = GetEncoderInfo(ImageFormat.Gif)
        Dim encCompressionrParameter As New EncoderParameter( _
          System.Drawing.Imaging.Encoder.Compression, CLng( _
          EncoderValue.CompressionLZW))
        Dim encQualityParameter As New EncoderParameter( _
        System.Drawing.Imaging.Encoder.Quality, 100L)
.......
NewImg.Save(strFile, myImageCodecInfo, myEncoderParameters)

Private Function Index_OfTransparency(ByVal pPal As ColorPalette, ByVal pCol As _
  Color) As Integer
        Dim i As Integer
 
        For i = pPal.Entries.Length - 1 To 0 Step -1
            If pPal.Entries(i).IsEmpty Then
                'überlesen
            ElseIf pPal.Entries(i).ToArgb = pCol.ToArgb Then
                Return i
            End If
        Next
        Return -1
    End Function