Copying images from one epub to another

I have two versions of my epubs - one is the original, and the other is the same file, but put through Bionic Reading, to change the font. I just discovered that for at least one book that I've put through BR, the images were not preserved.

I can manually extract the images from the original epub and manually insert them into the HTML but it's very painful and I'm worried about being spoiled for the content by doing this process. Does anyone here know a way to do this more easily or automate it?