On my end the images look the exact same as what is displayed in the Customizer. Keep in mind, that the images in the background are responsive, so they are designed to adjust depending on the size of the browser/screen.
I did fix a small issue that showed up in your first image. On certain screen sizes it would show white space on the sides. I commented out this code here –
@media only screen and (max-width: 1800px) {
/*.front-page-1,
.front-page-4,
.front-page-5,
.front-page-7,
.front-page-9,
.front-page-12 {
-webkit-background-size: auto;
-moz-background-size: auto;
background-size: auto;
}*/
}
This is located near the bottom of the CSS file in the responsive section.
Everything else looks fine to me. If there is a specific area that isn’t showing right on your end, just let me know.