[jttraverse]

I should have clarified that I realize zooming is a function of the reader. What I'm trying to understand is what makes one image zoomable when, in the same reader, another image is not zoomable.

I know that opening a regular plain-vanilla image (jpeg, png, etc.) yields a fully zoomable photo, but when I insert the image into an ePub book and then open the book, the image does not scale. So there must be something in the way it is being handled in the ePub format that makes it zoomable or not depending on the circumstances.

Thanks