My parallax images are shrinking. Why?

Help! Our parallax images have shrunk in the layout and will not retain their vertical size. What are we doing wrong?

For the parallax feature to work, some of the image has to be hidden until being revealed during scroll. This means images will be cropped.
 

If you are using a Brine-family template, you can minimise (but not eliminate) the cropping. In the Main: Overlay section If Site Styles, check Parallax Smart Crop.

Paul, sorry to piggy back but do you know why "Main Overlay" isn't appearing as an option for a new Index page?