ListView header icons do not show-up

[S.Br.]

Dear Mr. Excel; please take a look at the following script and tell me
why my column header icons do not show up:

' Microsoft Windows [Version 10.0.19045.5608]
' Microsoft® Excel® for Microsoft 365 MSO (Version 2502 Build 16.0.18526.20144) 64-bit
' Microsoft Visual Basic for Applications 7.1 Version 1146
' List View ActiveX Control - Version 6.0 (SP6)
' Image List ActiveX Control - Version 6.0 (SP6)

Option Explicit

Private Sub ListView1_ColumnClick(ByVal ColumnHeader As MSComctlLib.ColumnHeader)
  ' List View ActiveX Control - Version 6.0 (SP6)
  With ColumnHeader
    If .Icon = 0 Then
      .Icon = .Index
    Else
      .Icon = 0
    End If
  End With
End Sub

Private Sub UserForm_Initialize()
  With ImageList1
    .ImageHeight = 12
    .ImageWidth = 12
    With .ListImages
      .Clear
      .Add Picture:=LoadPicture(ThisWorkbook.Path & Application.PathSeparator & "img1.bmp")
      .Add Picture:=LoadPicture(ThisWorkbook.Path & Application.PathSeparator & "img2.bmp")
    End With
  End With
  With ListView1
    Set .ColumnHeaderIcons = ImageList1
    With .ColumnHeaders
      .Clear
      .Add Text:="HDR1", Icon:=1
      .Add Text:="HDR2", Icon:=2
    End With
    With .ListItems
      .Clear
      With .Add(Text:="ITEM1")
        .ListSubItems.Add Text:="subitem1"
      End With
      With .Add(Text:="ITEM2")
        .ListSubItems.Add Text:="subitem2"
      End With
    End With
  End With
End Sub

All I've put on the UserForm is just 2 controls: ImageList1 and ListView1. Many thanks in advance,
S.Br.