Excel visual basic (vba) resize and export all charts to png file

Sub LineUpMyCharts()

    Dim MyWidth As Single, MyHeight As Single

    Dim NumWide As Long

    Dim iChtIx As Long, iChtCt As Long

    MyWidth = 375

    MyHeight = 250

    NumWide = 2

    iChtCt = ActiveSheet.ChartObjects.Count

    For iChtIx = 1 To iChtCt

        With ActiveSheet.ChartObjects(iChtIx)

            .Width = MyWidth

            .Height = MyHeight

            .Left = ((iChtIx – 1) Mod NumWide) * MyWidth

            .Top = Int((iChtIx – 1) / NumWide) * MyHeight

        End With

        pngName = ActiveWorkbook.Path & "\png\" & iChtIx & ".png"

        ActiveSheet.ChartObjects(iChtIx).Activate

        ActiveChart.Export FileName:=pngName, FilterName:="PNG"

    Next

End Sub