Rails 4: SASS background image works locally, fails in AWS

Just updated to Rails 4 and now this style, which in history worked everywhere, and now only works locally:

#subfooter {
    width: 1160px;
    margin: 0 auto;
    padding: 45px 0 20px;
    background: url(ap@1x.png) no-repeat top left;
}

It fails in AWS. Anyone have any ideas about SASS/CSS loaded image differences across environments?

Thanks.