Hi Bart,
as nobody else has answered so far,
I think there is no straightforward way.
What else would then be left but "sendkeys"?
SendKeys "%a", 1
SendKeys "%w", 1
SendKeys "{ENTER}"
With ActiveDocument.CommandBars("Picture")
.Controls("Compress Pictures...").Execute
End With

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Greetings from Bavaria, Germany
Helmut Weber, MVP WordVBA
Win XP, Office 2003
"red.sys" & Chr$(64) & "t-online.de"