As brought up by rdickens and smumford over IRC this morning there currently isn't anyway to include a image at a fixed revision. This is needed if you want old books/topics to use the old image and new books to use a newer image (say an update to the products UI)
When talking to mcasperson over IRC a way to do this may be to allow a revision to be used in the <imagedata> reference. eg: <imagedata fileref="images/9:12343.png"/> which would reference image 9 at revision 12343. In saying that though we'd need BZ#833245 implemented first so users could see previous revisions.
In a real topic, you would have several image references, each frozen at revisions, with conditional tags for the version they are applicable to. It is a bit complex, but wouldn't have to be bad if you could auto-generate reasonable <img> XML code in the image preview area. Maybe you could have a pick-box of possible conditions and selecting one would add it to the example XML and you could copy&paste.