Change "Environment for all season" images f

Hello,

I want to change the two images on the home page for two new images keeping the "click to change" option. How do I do this?

I see from other posts how to remove it in layout.css but not how to replace them with alternative images

Cheers

In layout.css:

.fullwidth {
background: url(../images/custom/town_summer.jpg) no-repeat bottom;
background-size: cover;
}

and in index.php of template:
<script type="text/javascript">
jQuery(".subtext").toggle(
function () {
jQuery('.fullwidth').css('background-image','url(<?php echo $template_path; ?>/images/custom/town_winter.jpg)');
},
function () {
jQuery('.fullwidth').css('background-image','url(<?php echo $template_path; ?>/images/custom/town_summer.jpg)');
}
);
</script>