First, are you trying to export to fixed-page EPUB (FXL) or reflowable? (I'd suspect the former, from the nature of the problem.) The question is then why are you not using the generally superior reflowable format?
As for the problem itself, when you say "a series of images" — do you mean actual separate image files, or page-images within the exported file? If the latter, that's (more or less) exactly what FXL format is, each page rendered using graphical elements and very complex HTML layout to present something very similar to a print page.
Need a little more info here to help. 🙂
And just to jump ahead a little in likely problem areas, templates are not usually a good choice for complex projects by users who aren't masters of whatever format and features are involved. They often bring, or lead to, as many problems as they solve.
Also, what EPUB viewer are you using — assuming you are getting far enough to have a viewable file? EPUB results are entirely dependent on using a compatible, standard viewer. If you're using Adobe's, you need to switch to one that actually, you know, works. 🙂
╟─ Word & InDesign to Kindle & EPUB: a Guide to Pro Results (Amazon) ─╢