#bg{position:fixed;top:-50%;left:-50%;width:200%;height:200%;z-index:-1000;}#bg img{position:absolute;top:0;left:0;right:0;bottom:0;margin:auto;min-width:50%;min-height:50%;}@media screen and (max-width: 1024px){#bg img{left:50%;margin-left:-512px;}}