image compression using vb.net

Private Class JpegTools
     Private codecs As ImageCodecInfo() = ImageCodecInfo.GetImageEncoders()
     Private quality As Long

     Public ici As ImageCodecInfo = Nothing
     Public ep As New EncoderParameters()
     Public compressionRatio As Long

     Public Sub new(ByVal _compressionRatio As Long, Optional ByRef errMsg As String = "")

         compressionRatio    = _compressionRatio
         If compressionRatio < 0 then compressionRatio = 0
         If compressionRatio > 100 then compressionRatio = 100
         quality             = (100 - compressionRatio)

         Try
             For Each codec As ImageCodecInfo In codecs
                 If codec.MimeType = "image/jpeg" Then
                     ici = codec
                 End If
             Next

             ep.Param(0) = New EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality)
         Catch ex As Exception
             errMsg = ex.Message
         End Try
     End Sub
 End Class

 Private JpgTools As JpegTools

 ' Save an Image() to a jpeg file and specify the compression % (Valid values for compressionRatio are 0 - 100)
 Public Function SaveImgToFile(ByRef img As Image, ByVal fullPathWithFileName As String, ByVal compressionRatio As Long, _
                               Optional ByRef errMsg As String = "") As Boolean

     If JpgTools Is Nothing Then JpgTools = New JpegTools(compressionRatio, errMsg)
     If JpgTools.compressionRatio <> compressionRatio then JpgTools = New JpegTools(compressionRatio, errMsg)
     If errMsg <> "" then Return False

     Try
         img.Save(fullPathWithFileName, JpgTools.ici, JpgTools.ep)
     Catch ex As Exception
         errMsg = ex.Message
         Return False
     End Try

     Return True
 End Function