What's the difference between fill and fit?
Fill and fit are two image display sizes in the app. The full size image is always available; just tap the hero image at the top of the screen.
Fill
Automatically zoom in on the center of the image, so the image fills all available space.
Fit
Automatically resize the image so it fits inside the available space, without cutting off any parts of the image. This option often results in a smaller image with padding on the sides.
For more on updating your guide's default, see Update image display defaults.