Well, I was curious about how fixed-layout books work in my Kindle for iPad app... so I purchased a children's Halloween picture book which was just published. I sent it first (when I bought it) to my iPad... cute book but not fixed-layout... no page breaks, not a good children's picture book experience. But then I sent it to my KindleFire... and the results were the same. Looked exactly alike. I'm sure if I looked at the epub version of the book on the iPad, it would be a picture book... one picture and text on each page.
I'm thinking you should incorporate the text into the image for it to work property.