Hi Melissa.
Please follow these steps:
1 Delete or comment all code that you have done before.
2 Open needed page and activate page mobileContainer. http://prntscr.com/3mnk70/direct
3 Set for this component "class name" as "myPageContentClass" http://prntscr.com/3mnkik/direct
4 Create new CSS asset. http://prntscr.com/3mnkog/direct
5 Populate it with following code: http://prntscr.com/3mnktm/direct
precode
.myPageContentClass{
background: url(https://encrypted-tbn3.gstatic.com/images?q=tbn:ANd9GcTnLsVtG7ev0G3wmg9ASTGhtuQYIrHICdDLrk31fzCYZAIAh84JiQ);
}
/code/pre
That's all. Test it and you will get something like this: http://prntscr.com/3mnl5i/direct
Regards.