Issue inserting JPEG containing into Workbook

[NewOrderFac33]

Good afternoon,
I have an area of my worksheet containing pie charts that I export to a JPEG at different points in the week - the idea being that I'm taking a "snapshot" of the piecharts at different points in time, to allow me to compare them over a period.
The code creates a new worksheet, exports the range to a JPEG, then inserts the JPEG to the new worksheet.
This all works fine, except when I close the workbook and re-open it, at which point all the JPEGs in the inserted change to the most recent one.
It's as though there is a hyperlink between each JPEG and the most recently created version of it on disk, but I can't find anything.
Here's the code I uses to create the JPEG:

Sub Create_JPEG_TM_04()
    Sheets("MySheet").Activate
    Application.GoTo Reference:="TM_04"
    vFilePath1 = "J:\MyPic"
    SlideErrorMessage = "Sorry - I couldn't create the TM_04 JPEG - Please try again!"
    Range("TM_04").Select
    Create_JPEG
End Sub


Sub Create_JPEG()
    'Procedure exports selected range to JPEG file
    'Default filename is WorkbookName+SheetName+RangeAddress.JPG
 
    If TypeName(Selection) <> "Range" Then
        MsgBox "Selection is not a range of cells."
        Exit Sub
    End If
    
    'On Error GoTo ExportError
    
    CurrentSheetName = ActiveSheet.Name
    'Sheets("Stats").Activate
    CurrentZoom = ActiveWindow.Zoom
    ActiveWindow.Zoom = 200
    
    ChDrive ("J:")
    ChDir ("J:\Build and Release\Management\BRMgtPresPack\")
    vFilePath2 = vFilePath1 & ".jpg"
    
    With Selection
       
       'Make picture of selection and copy to clipboard
       .CopyPicture Appearance:=xlScreen, Format:=xlBitmap
   
       'Create an empty chart with exact size of range copied
        With ActiveSheet.ChartObjects.Add( _
            Left:=.Left, Top:=.Top, Width:=.Width, Height:=.Height)
            .Name = "TempChart"
            .Activate
        End With
    
    End With
 
    'Paste into chart area, export to file, delete chart.
    ActiveChart.Paste
    
    With ActiveSheet.ChartObjects("TempChart")
        .Chart.Export CStr(vFilePath2)
        .Delete
    End With
    
    ActiveWindow.Zoom = CurrentZoom
    ActiveWindow.DisplayZeros = False
    Sheets(CurrentSheetName).Activate
    Exit Sub
    
ExportError:
    MsgBox (SlideErrorMessage)
    ActiveWindow.Zoom = CurrentZoom
    Sheets(CurrentSheetName).Activate


End Sub

and here's the code I use to create the new worksheet and import the previously saved JPEG:

Sub ImportArchive()
    Sheets.Add After:=Sheets(Sheets.Count)
    MySheetName = Format(Now(), "ddd dd-mmm-yy hh-mm")
    ActiveSheet.Name = MySheetName
    ActiveWindow.DisplayGridlines = False
    Range("A1").Select
    Selection.Value = Now()
    With Selection.Font
        .Name = "Arial"
        .Size = 16
        .Bold = True
    End With
    Selection.NumberFormat = "ddd dd-mm-yyyy hh:mm"
    Application.GoTo Reference:="R2C1"
    ActiveSheet.Pictures.Insert("J:\MyPic").Select
End Sub

Can anyone hep, please?
Thanks in advance
Pete