var calcHeight=function(){$('#contenu').height($(window).height()-220);}
$(window).resize(function(){calcHeight();}).load(function(){calcHeight();});

$(document).ready(function(){
	$(".download").find("img").css('opacity',.7);
	$(".download").hover(
		function(){$(this).find("img").stop(true,true).animate({opacity:1},200);},
		function(){$(this).find("img").animate({opacity:.7},200);}
	);
});