Демо CSS: background-image

background-image: url("../../media/examples/lizard.png");

background-image: url("../../media/examples/lizard.png"),
                    url("../../media/examples/star.png");

background-image: url("../../media/examples/star.png"),
                    url("../../media/examples/lizard.png");

background-image: linear-gradient(rgba(0, 0, 255, 0.5), rgba(255, 255, 0, 0.5)),
                    url("../../media/examples/lizard.png");