function riders() {
	var imgHeight = 1000;
	var imgWidth = 2500;
	var boxWidth = $('#riders').width();
	var scale = imgWidth/boxWidth;
	var maxHeight = imgHeight/scale;
	$('#riders').css({ height: maxHeight });
	
	$(window).resize(function() {
		var boxWidth = $('#riders').width();
		var scale = imgWidth/boxWidth;
		var maxHeight = imgHeight/scale;
		$('#riders').css({ height: maxHeight });
	});
}