Excel save all charts

'small nicety to ensure two-digits for better file sorting'
Function NiceFileNumber(num As Integer) As String
    If num < 10 Then
        NiceFileNumber = "0" & num
    Else
        NiceFileNumber = num
    End If
End Function

'the real function'
Sub ExportAllCharts()
    Dim i As Integer, exportCount As Integer
    Dim fileNum As String, fileBase As String
    Dim sheetObj As Worksheet
    Dim chartObj As Chart

    'current file location and name, with extension stripped'
    fileBase = Left(ThisWorkbook.FullName, InStrRev(ThisWorkbook.FullName, ".") - 1)
    exportCount = 0

    'First, export all charts that are in their own sheets'
    For Each chartObj In ActiveWorkbook.Charts
        fileNum = NiceFileNumber(exportCount)
        exportCount = exportCount + 1

        'Do the export'
        chartObj.Export fileBase & "_chart" & fileNum & ".png"
    Next

    'Then, export all charts that are embedded inside normal sheets'
    For Each sheetObj In ActiveWorkbook.Worksheets
        For i = 1 To sheetObj.ChartObjects.Count
            fileNum = NiceFileNumber(exportCount)
            exportCount = exportCount + 1

            'Do the export'
            sheetObj.ChartObjects(i).Activate
            ActiveChart.Export fileBase & "_chart" & fileNum & ".png"
        Next i
    Next

    MsgBox "DONE"
End Sub