同一元素背景css下放多个图片

.bg{ width:100%; height:500px;

 background-image:url(image/parallax_octocat.png), url(image/ProfileIconDouban.png), url(image/caomei_02.jpg); 

background-position:center center,  50px center,top;
background-repeat:no-repeat, no-repeat, repeat-x; background-clip:padding;}