以下内容不涉及图像的位置，但允许您在添加新图像之前删除前一个图像。
您可以使用全局变量来存储对旧图像的引用（而不是额外的工作表），但如果VBA丢失了引用或您保存/重新加载Excel，则引用将丢失，因此您需要更多代码来在保存之前删除图像，并检查丢失的图像等。

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
On Error Resume Next
Dim Sheet As Worksheet
Dim Image As Shape

Set Sheet = ThisWorkbook.Worksheets("hidden")

Set Image = ActiveSheet.Shapes(Sheet.Cells(1, 1).Value)

If Target.Column = Range("C:C").Column Then

    If Not Image Is Nothing Then Image.Delete

    Set Image = ActiveSheet.Shapes.AddPicture( _
        Filename:=ActiveCell.Offset(0, 7).Value, _
        LinkToFile:=msoFalse, _
        SaveWithDocument:=msoTrue, _
        Left:=ActiveCell.Offset(0, 5).Left, _
        Top:=ActiveCell.Top, _
        Width:=400, Height:=400)
    
    Sheet.Cells(1, 1).Value = Image.Name

    Exit Sub

End If

End Sub

如果您的工作表没有任何其他图像/形状，您也可以执行以下操作

Private Sub Worksheet_SelectionChange(ByVal Target As Range)
Dim Image As Shape

If Target.Column = Range("C:C").Column Then

    ' delete all shapes
    For Each Image In ActiveSheet.Shapes
        Image.Delete
    Next

    Set Image = ActiveSheet.Shapes.AddPicture( _
        Filename:=ActiveCell.Offset(0, 7).Value, _
        LinkToFile:=msoFalse, _
        SaveWithDocument:=msoTrue, _
        Left:=ActiveCell.Offset(0, 5).Left, _
        Top:=ActiveCell.Top, _
        Width:=400, Height:=400)

    Exit Sub

End If

End Sub