In my app I created a homescreen with icons in grid layout. Adding a background image to this page is done by adding a custom css class ‘background’:
<ion-content class="background" scroll="false">
In your CSS file add an entry for ‘.background.scroll-content’:
/* homescreen background image */
.background.scroll-content {
background: url('../img/mybackground.png') no-repeat;
background-size: cover;
}