div{
    width: 300px;
    height: 100px;
    border: 5px dashed #333;
    padding: 10px;
    margin: 10px auto;
    background-color : RGBa(255, 255, 255, 0.2);
}

#ex1, #ex2, #ex3, #ex4{
    background-image: url("../images/smile.png");
    background-repeat: no-repeat;
}
#ex1{
    background-origin : border-box;
    background-clip : border-box;
}
#ex2{
    background-origin : border-box;
    background-clip : content-box;
	/*border moins padding*/
}
#ex3{
    background-origin : content-box;
    background-clip : border-box;
}
#ex4{
    background-origin : content-box;
    background-clip : content-box;
	/*le padding est visible*/
}