png文件上的颜色蒙版

<div class=\"red\"></div>
<div class=\"magenta\"></div>
<div class=\"blue\"></div>

div {
    background: url(http://i.stack.imgur.com/LliRn.png);
    width: 320px;
    height: 60px;
    margin: 0 0 10px 0
}
.red {
    background-color: red
}
.magenta {
    background-color: #f0f
}
.blue {
    background-color: blue
}