Make your images grow to fill the space in the Orbit stack
Since the Orbit stack is responsive you’ll likely want your images to not only scale down for when your visitors are viewing your site on mobile devices, but you’ll also want them to scale upwards to fill out the area on desktop browsers.
This is done by selecting the “Unlimited” option in the Image Scaling setting in Orbit’s settings. This will cause the image to scale too fill the container it is located within in your layout. This could mean that it would scale up to the full content area’s available width, or just the width of the column you’ve put it inside of in a slide. It all depends on your layout.