The [Insert] button in the "Insert picture" dialogue* is a pulldown, offering

• insert
• link to file
• insert and link

I've heard horror stories about documents where one fine day all the links fall off, and I don't find Word's options for managing linked graphics particularly convincing … but YMMD: see if one of the link options does what you want.

I entirely agree with you that using a link is the way to handle repeated graphics; and in my usual environment I have never, ever pasted in a graphic. Working with links makes it a snip to check what graphics have been referenced in the document, and instantly updates the document when I need to change the graphic.

* at least, that's the way it is in 2010