Well, from the first glance it looks like your loop will never exit. If there are any shapes in the document, this line:
will never test true.
Do Until ActiveSheet.Shapes.Count = 0
Do you want all of the images resized, or just ones that meet a specific criteria? This will resize all of them:
Originally Posted by BUYAMAC
If you only want to resize some of them, you'll have to add some sort of test to determine if the oShape is one that fits your criteria.
Public Sub ResizePics()
Dim oDoc As Document, oShape As InlineShape
Set oDoc = Application.ActiveDocument
For Each oShape In oDoc.InlineShapes
oShape.Height = 270
oShape.Width = 360
Set oDoc = Nothing