2.1.1733 Part 4 Section, LinkType (Embedded Object Alternate Image Request)

a.   The standard does not specify a default value for the LinkType element.

Office uses a default value of Bitmap for the LinkType element.

b.   The standard indicates how the LinkType element is used.

n Office, the LinkType element only works for linked objects, which are objects for which the value of the Type attribute on the OLEObject element is Link.