If you're just trying to preload the background image, you could do something like this:
$(document).ready(function() {
$('#preLoader').show();
$('#container').hide();
$('<img>', {src: '/url/of/image.jpg'}).load(function() {
$('#preLoader').hide();
$('#container').show();
}).error(function() {
// Something went wrong
});
});
A better alternative would be to use the waitForImages plugin:
$(document).ready(function() {
$('#preLoader').show();
$('#container').hide();
$(document).waitForImages(function() {
$('#preLoader').hide();
$('#container').show();
});
});