Are you saying you want the background to be white? Or do you want the text to be white with a background image? We can manually add this in through the CSS, or through the Customizer CSS section.
Example, if you added this to the Customizer CSS section, then the background image will show up on the homepage only (not the rest of the site) –
.home-feature-7 {
-webkit-background-size: cover;
-moz-background-size: cover;
background: url("http://grassrootsrockwall.com/wp-content/uploads/2017/02/lawn-service-rockwall-hm-1.jpg");
background-attachment: fixed;
background-position: center;
background-repeat: no-repeat;
background-size: cover;
clear: both;
}
It looks like you uploaded a background image for the main BODY of your site and that’s why it’s showing up on other pages as well.
Until I’m able to get the update done for the inSync theme, I would add background images using CSS for now. I can help you with this so you won’t have to worry about dealing with the code. Just let me know.