The Studio Press Infinity Pro theme includes a filter for customizing which front page images can have background images configured through the WordPress customizer. This snippet, when added to the theme's /lib/helper-functions.php file, will allow you to add images to all of the front page widget areas.
If you don't want all widget areas to have background images, just remove the number from the array. The default is 1,3,5,7. One last step to finalize this, edit front-page.php and change the solid section class to image-section for any area to which you are adding an image.