Hello,
Login to your admin dashboard and go to Appearance > Customizer > Design Options > Custom CSS
and paste the below custom CSS code to set the different background image for each page.
.page-id-561 {
background-image: url(add-full-image-url-here);
background-position: center center;
background-repeat: no-repeat;
background-size: cover;
}
Note: Add your the page id in above digit value 561
and add the full image url in add-full-image-url-here
text above and for another page copy paste above code and repeat the same action to set different background image for another page.
Thank you for using our theme.