Replace text in cell with picture (or insert picture into same cell)

[plainhavoc]

The Event macro asks you to confirm the row you use for z.1 etc.

Private Sub Worksheet_change(ByVal Target As Range)
    'adjust to suit
    If Target.Row <> 1 Then Exit Sub

I guess this is where my understanding is less than adequate. Where would this be called in the module? Also, there could be multiple instances of "z.1", etc. throughout the spreadsheet (though never more than one per cell).

Attached is the current semi-working xlsm for reference.