Oscar Sun

                  Sub pic透明(r As Range)
Dim inlshape As InlineShape
For Each inlshape In r.InlineShapes
    With inlshape.PictureFormat 'https://msdn.microsoft.com/zh-tw/VBA/Word-VBA/articles/pictureformat-transparentbackground-property-word
                                'https://msdn.microsoft.com/zh-tw/VBA/Word-VBA/articles/inlineshape-pictureformat-property-word
        .TransparentBackground = msoTrue '背景透明
        .TransparencyColor = RGB(255, 255, 255) '字黑色
    End With
Next inlshape
End Sub

'https://stackoverflow.com/questions/38305617/apply-a-picture-style-to-all-pictures-in-a-word-document#_=_
'https://msdn.microsoft.com/zh-tw/VBA/Word-VBA/articles/shadowformat-transparency-property-word
'https://msdn.microsoft.com/zh-tw/VBA/Word-VBA/articles/pictureformat-transparentbackground-property-word?f=255&MSPPError=-2147217396