Sub Demo()
Dim iShp As InlineShape
With Selection ' or ActiveDocument
  For Each iShp In .InlineShapes
    With iShp
      .LockAspectRatio = True
      .Height = CentimetersToPoints(3.5)
      With .Line
        .ForeColor.RGB = RGB(0, 0, 0)
        .Weight = 0.5
        .Visible = True
        .Style = msoLineSingle
      End With
      With .Range.ParagraphFormat
        .Alignment = wdAlignParagraphCenter
        .LineSpacingRule = wdLineSpaceSingle
      End With
    End With
  Next
End With
End Sub