This example scales all pictures and OLE objects on myDocument
to 175 percent of their original height and width, and it scales all other shapes to 175 percent of their current height and width.
Set myDocument = ActivePresentation.Slides(1)
For Each s In myDocument.Shapes
Select Case s.Type
Case msoEmbeddedOLEObject, msoLinkedOLEObject, _
msoOLEControlObject, msoLinkedPicture, msoPicture
s.ScaleHeight 1.75, True
s.ScaleWidth 1.75, True
Case Else
s.ScaleHeight 1.75, False
s.ScaleWidth 1.75, False
End Select
Next