Okay i have this same issue...my background image is not loading yet I use the same exact code in another app and it loads fine. Here is the code that works fine:
Tiggzi("mobilecontainer10").css('background-image','url("' + Tiggzi.getImagePath
('background3.png') + '")');
Tiggzi("mobilecontainer10").css('background-size','cover');
Tiggzi("mobilecontainer10").css('background-position','center');
Tiggzi("mobilecontainer10").css('position', 'absolute');
Tiggzi("mobilecontainer10").css('width', '100%');
Here is the code to the app that is not loading:
Tiggzi("mobilecontainer10").css('background-image','url("' + Tiggzi.getImagePath('MISC194.png') + '")');
Tiggzi("mobilecontainer10").css('background-size','cover');
Tiggzi("mobilecontainer10").css('background-position','center');
Tiggzi("mobilecontainer10").css('position', 'absolute');
Tiggzi("mobilecontainer10").css('width', '100%');