#hide-slide {
	display:none;
	}
------------------------------------
<div id=hide-slide>
	<?php the_content(); ?>
</div>
------------------------------------
<script>
	jQuery(document).ready(function($) {
		$('body').each(function() {
			var imageUrl = $('#hide-slide').find(">:first-child").attr('src');
			$(this).css('background-image', 'url(' +imageUrl+ ')');
		});
	});
</script>