problem with image resize function

the function
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Public Function ProportionallyResizeBitmap(ByVal src As Bitmap, ByVal maxWidth As Integer, ByVal maxHeight As Integer) As Bitmap
        Dim w As Integer = src.Width
        Dim h As Integer = src.Height
        Dim longestDimension As Integer = IIf((w < h), w, h)
        Dim shortestDimension As Integer = IIf((w > h), w, h)
        Dim factor As Single = CSng(longestDimension) / shortestDimension
        Dim newWidth As Double = maxWidth
        Dim newHeight As Double = maxWidth / factor
        If w < h Then
            newWidth = maxHeight / factor
            newHeight = maxHeight
        End If
        Dim result As New Bitmap(CInt(newWidth), CInt(newHeight))
        Using g As Graphics = Graphics.FromImage(DirectCast(result, System.Drawing.Image))
            g.DrawImage(src, 0, 0, CInt(newWidth), CInt(newHeight))
        End Using
        Return result
    End Function
 
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how I call the function to upload and copy it to its destination
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If FileUpload1.FileName <> "" Then
 
            'thubnail creation and upload
            Dim fileName As String = FileUpload1.FileName
            Dim src As Bitmap = TryCast(Bitmap.FromStream(FileUpload1.PostedFile.InputStream), Bitmap)
            Dim resultThumb As Bitmap = ProportionallyResizeBitmap(src, 200, 200)
            Dim saveName As String = Server.MapPath(savePath) + fileName
            resultThumb.Save(saveName, ImageFormat.Jpeg)