Try this for the first option

Sub killPLC()'kill empty pic placeholders
Dim osld As Slide
Dim S As Long
Dim counter As Long
For Each osld In ActivePresentation.Slides
    For S = osld.Shapes.Count To 1 Step -1
        With osld.Shapes(S)
            If .Type = msoPlaceholder Then
                If .PlaceholderFormat.Type = ppPlaceholderPicture Then
                    If Not .PlaceholderFormat.ContainedType = msoPicture Then
                        .Delete
                        counter = counter + 1
                    End If
                End If
            End If
        End With
    Next S
Next osld
MsgBox counter & " Placeholders deleted."
End Sub