Изменение размера 

Sub resize()
Dim i As Long
With ActiveDocument
 For i = 1 To .InlineShapes.Count
 With .InlineShapes(i)
 .Height = 500
 .Width = 600
 End With
 Next i
End With
MsgBox "Готово.", vbInformation
End Sub

Масштабирование, вариант 1

Sub resize()
Dim i As Long
With ActiveDocument
 For i = 1 To .InlineShapes.Count
 With .InlineShapes(i)
 .ScaleHeight = 100
 .ScaleWidth = 100
 End With
 Next i
End With
MsgBox "Готово.", vbInformation
End Sub 


Мастштабирование, вариант 2

Sub AllPictSize()
       Dim PercentSize As Integer
       Dim oIshp As InlineShape
       Dim oshp As Shape
    
       PercentSize = InputBox("Enter percent of full size", "Resize Picture", 100)
    
       For Each oIshp In ActiveDocument.InlineShapes
           With oIshp
               .ScaleHeight = PercentSize
               .ScaleWidth = PercentSize
           End With
       Next oIshp
    
       For Each oshp In ActiveDocument.Shapes
           With oshp
               .ScaleHeight Factor:=(PercentSize / 100), _
                 RelativeToOriginalSize:=msoCTrue
               .ScaleWidth Factor:=(PercentSize / 100), _
                 RelativeToOriginalSize:=msoCTrue
           End With
           MsgBox "Готово.", vbInformation
       Next oshp
   End Sub