An example of that is one ebook where the author used graphics for the chapter headers. Looked great until you recreated the ToC and either manually edited in the chapter numbers or added them using title=. I ended up selecting all the chapter images and renaming the them into a usable format and then a simple regex did the deal.
<h3 class="chapnum" title="Chapter 18"><img class="glyphw25" src="../Images/chapter_18.jpeg" alt="Chapter 18"/></h3>