$('#content').waitForImages(function() {
	//console.log('content loaded');
	$bar.css({
		width: '100%'
	});

	$c.fadeOut('slow');
}, function(loaded, count, success) {
	var p = (loaded / count) * 100;
	//console.log(p);
	//console.log(loaded + ' of ' + count + ' images has ' + (success ? 'loaded' : 'failed to load') +  '.');
	$bar.css({
		width: p + '%'
	});
}, 
true);

The third param is very important! Set it “true” to include background images.

Reference:

• https://github.com/alexanderdickson/waitForImages