Hey there! I've been using the standard background cover CSS code for my project, which usually does the trick. Here's the code:
-webkit-background-size: cover !important;
-moz-background-size: cover !important;
-o-background-size: cover !important;
background-size: cover !important;
background-position: left top;
background-repeat: repeat;
background-attachment: scroll;
Everything looks good most of the time, but when I resize the window to be taller than it is wide, something unexpected happens. It seems like setting the size to cover should just make the image taller, not leave white space underneath it.