Your images are actually not big enough at 512px x 341px. Your images should be at least 1950px wide. The images are scaled to fit the browser width, when you images are scaled up this naturally makes them much taller as well.
So you need to make your image 1950px wide and only as tall as you actually need it to be (i.e. more letter-box shaped).
The following users have thanked you: Michael D'Avis
- Please search forums before posting. Please make sure your post includes the version of the CMS you are using and a link to the problem. Annotations on screenshots can also be helpful to explain problems/goals. Please use the "secure" tab for confidential information.