Missing images when importing an ePub3

I used Book Creator app on my iPad Mini to create a comic book. I exported it to my Google Drive as an ePub and then downloaded it to my MacBook Air. In iBooks Author I used "New from ePub file" to create a new book. This book was missing several images. The audio and video files came through with no problems, 2 images from about 30 total. When I view the book in iBooks on the MacBook Air it shows all the images. What am I missing?

Book Creator app version 4.2.2

iPad Mini iOs 9.3

MacBook Air 10.11.3

iBooks Author 2.4 (816)