how to make background image overlay html 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: how to add a background overlay in css

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