how to add overlay to background image css code example

Example 1: background overlay css

html {
  min-height:100%;
  background:linear-gradient(0deg, rgba(255, 0, 150, 0.3), rgba(255, 0, 150, 0.3)), url(http://lorempixel.com/800/600/nature/2);
  background-size:cover;
}

Example 2: background image overlay

html {
  background:url(http://lorempixel.com/800/600/nature/2);
  background-size:cover;
  box-shadow:inset 0 0 0 2000px rgba(255, 0, 150, 0.3);
}

Example 3: css background overlay

.image:before{
    content: "";
        background: rgba(0,0,0,.6);
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 24px;
}

Example 4: how to add a background overlay in css

.header {
  background: rgba(0, 0, 0, 0.5); /* Black color with 50% alpha/opacity */
}