Hi,
Because of the background template overrides loaded.
Go to: templates/if_calla-exteriors/css/template.css
Line 335. We can remove and using jf slideshow.
# {jf-slideshow
background-clip: border-box;
background-color: # 00446D;
background-image: url (.. / images / banner.jpg);
background-origin: padding-box;
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
background-attachment: fixed;
position: relative;
z-index: 50;
}