Full-screen zoom works for slide shows, but can I use it for a single image as well ?
Using the 'Graphic' option of the Twixl Publisher palette, you can add an image that will be viewable in full screen.
"Allow Full Screen View": double-tapping an image toggles a
full-screen view of the image.
If you are using transparency in your image, then use 'PNG'.
Otherwise you can export as 'JPG'.