.item {
float: left;
21%;
margin: 10px 2%;
height: 0;
padding-bottom: 21%;
background: red url('http://www.51nyc.com/statics/images/info/logo.png') no-repeat;
background-size: contain;
background-position: center;
}
.gray {
-webkit-filter: grayscale(100%);
-moz-filter: grayscale(100%);
-ms-filter: grayscale(100%);
-o-filter: grayscale(100%);
filter: grayscale(100%);
filter: gray;
}
HTML代码:
<img src="http://image.zhangxinxu.com/image/study/s/s256/mm1.jpg" />
<img src="http://image.zhangxinxu.com/image/study/s/s256/mm1.jpg" class="gray" />