[jgoguen]

I'd be inclined to blame the book creator. That sounds like a chapter defined before the image, a chapter defined for the image, and a chapter afterward. It could also possibly be calibre's conversion settings, depending on how you created the KePub or if you ever did any conversions on the original book file.

You may find some answers if you go to Edit Book (right-click the book in calibre to see this option) and look at the Table of Contents.