If you’re using an older version of the theme then it’s probably missing the responsive code that was added for the slider backgrounds –
/* Desktops, laptops and iPads (landscape)
--------------------------------------------- */
@media only screen and (max-width: 1140px) {
.slider {
/*-moz-background-size: auto;*/
/*-webkit-background-size: auto;*/
background-attachment: scroll;
/*background-position: top;*/
/*background-size: auto;*/
}
}
Adding that should fix it.
It’s already available in the theme/download, I just needed to update the demo site. Version 1.1 is the latest.