how to add opacity to background image in css code example

Example 1: set background image opacity

#bg{
background-image: url('images/wood1.jpg');
opacity:0.2;
width:300px;
height:300px;
}

Example 2: background-image: url opacity

background-image: url(IMAGE_URL); /* fallback for older browsers */

background-image: linear-gradient(to bottom, rgba(0,0,0,0.6) 0%,rgba(0,0,0,0.6) 100%), url(IMAGE_URL);

Example 3: css opacity example

.opacity30 {
  opacity: 0.3;
  filter: alpha(opacity=30); /* For IE8 and earlier */
}

Example 4: background image opacity css

body::before{
    content: "";
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    z-index: -1;
    background-image: url(image.jpg); /*Put your image url*/
    background-size: cover;
    background-position: center;
    opacity: 0.25; /*Value from 0.0 to 1.0*/
}

Example 5: background image opacity css

/* Two ways to make images opaque */

div {
	background-color : rgba(120, 120, 120, 0.5) 
   	/* the 0.5 is the value of opacity on a scale of 0-1 */
}

/* OR */

div {
	background-color : blue
    opacity : 50%
}

Example 6: css background image opacity

/*
  You have to fake it, as there is no such property
*/

div {
  width: 200px;  /* Image Width */
  height: 200px; /* Image Height */
  display: block;
  position: relative;
}

div::after {
  content: "";
  background: url(image.jpg);
  opacity: 0.5;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  position: absolute;
  z-index: -1;   
}