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

#ex1, #ex2, #ex3{
    background-image: 
	url("../images/sunset.jpg");

    background-repeat: no-repeat;
}
#ex1{
    background-origin: border-box;
}
#ex2{
    background-origin: padding-box;
}
#ex3{
    background-origin: content-box;
	/*dans padding*/
}