Thanks Andrew.
I tried enabling the background on these pages:
Page: right sidebar
Page: full-width
Page: left sidebar
and I get this error and no background on the pages:
Warning: Invalid argument supplied for foreach() in /home/content/59/9333559/html/v2013/wp-content/themes/Rossi/includes/supersized/includes/WPSupersized.php on line 122
Warning: Invalid argument supplied for foreach() in /home/content/59/9333559/html/v2013/wp-content/themes/Rossi/includes/supersized/includes/WPSupersized.php on line 122
Warning: Invalid argument supplied for foreach() in /home/content/59/9333559/html/v2013/wp-content/themes/Rossi/includes/supersized/includes/WPSupersized.php on line 122