I am assuming you are referring to that bar under the form's title....
That comes with the Access templates (at least it did in 2007). In mine it is called GlassBanner.png. Yours appears to be called: office.png
I have never been able to add it to forms at will but have not tried very hard.
Perhaps it is possible do download the image and use it in Picture (under properties>format) as it is used here.