EPUB text flows
therefore... You don't have text if it is too big for the page.
It is a (scanned?) Image of text
Set your device Output Profile (Preferences: Common Options: page Setup) for
a device that has a similar screen size (pixels) . eBookwise is no a listed profile, therefor you will need to choose something similar. the description for each device will show on the right
Future conversions will scale the images to fit.
the Preferences only sets the Defaults for new books. You can use a similar option on the conversion screen or use the Reset settings button to retrieve the current Defaults. Every book remembers the settings that were used during that conversion