Scrolling presentation not resizing image for mobile

Site is at almamoto.com, the home page is using the scrolling presentation mode – on mobile the images do not resize.

I have added the CSS I found on another topic to center the images:

.fp-section.fp-table, .fp-slide.fp-table {
background-position: center center;
}

but I’d also like to resize them to mobile. The other pages / templates do this (see Adventure Delivery or Subscribe & Ride for reference).

Is there CSS I can add to resize images in the scrolling presentation as well?