html - Change background image opacity

Question

I have a div element with text blocks and a parent div in which I have set a background image. Now I want to reduce the opacity of the background image. Please suggest how I can do that.

Thanks in advance.

EDIT:

I am looking to change the way my blog post looks at blogger.com by editing the html content. The html code looks as follows:

<div>
 //my blog post
</div>

I tried to surround the whole code above with a div element and set opacity of each div separately as below:

<div style="background-image:url("image.jpg"); opacity:0.5;">
<div style="opacity:1;">
 //my blog post
</div>
</div>

But it is not working.

Answer 1

Nowadays, it is possible to do it simply with CSS property "background-blend-mode".

<div id="content">Only one div needed</div>

div#content {
    background-image: url(my_image.png);
    background-color: rgba(255,255,255,0.6);
    background-blend-mode: lighten;
    /* You may add things like width, height, background-size... */
}

It will blend the background-color (which is white, 0.6 opacity) into the background image. Learn more here (W3S).

Answer 2

You can't use transparency on background-images directly, but you can achieve this effect with something like this:

http://jsfiddle.net/m4TgL/

HTML:

<div class="container">
    <div class="content">//my blog post</div>
</div>​

CSS:

.container {  position: relative; }

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

.content {
    position: relative; 
    z-index: 2;
}​

Answer 3

Try doing this:

.bg_rgba {
  background-image: url(https://picsum.photos/200);
  background-color: rgba(255, 255, 255, 0.486);
  background-blend-mode: overlay;
  width: 200px;
  height: 200px;
  border: 1px solid black;
}

<div class="bg_rgba"></div>

worked in my case. You can reduce or increase the background-color alpha value according to your needs.

Answer 4

There is nothing called background opacity. Opacity is applied to the element, its contents and all its child elements. And this behavior cannot be changed just by overriding the opacity in child elements.

Child vs parent opacity has been a long standing issue and the most common fix for it is using rgba(r,g,b,alpha) background colors. But in this case, since it is a background-image, that solution won't work. One solution would be to generate the image as a PNG with the required opacity in the image itself. Another solution would be to take the child div out and make it absolutely positioned.

Answer 5

You can create several divs and do that:

<div style="width:100px; height:100px;">
   <div style="position:relative; top:0px; left:0px; width:100px; height:100px; opacity:0.3;"><img src="urltoimage" alt=" " /></div>
   <div style="position:relative; top:0px; left:0px; width:100px; height:100px;"> DIV with no opacity </div>
</div>

I did that couple times... Simple, yet effective...

Answer 6

You can also simply use this:

.bg_rgba {
  background: linear-gradient(0deg, rgba(255, 255, 255, 0.9), rgba(255, 255, 255, 0.9)), url('https://picsum.photos/200');
  width: 200px;
  height: 200px;
  border: 1px solid black;
}

<div class='bg_rgba'></div>

You can change the opacity of the color to your preference.

Answer 7

Responding to an earlier comment, you can change the background by variable in the "container" example if the CSS is in your php page and not in the css style sheet.

$bgimage = '[some image url];
background-image: url('<?php echo $bgimage; ?>');

Answer 8

What I did is:

<div id="bg-image"></div>
<div class="container">
    <h1>Hello World!</h1>
</div>

CSS:

html {
    height: 100%;
    width: 100%;
}
body {
    height: 100%;
    width: 100%;
}
#bg-image {
    height: 100%;
    width: 100%;
    position: absolute;
    background-image: url(images/background.jpg);
    background-position: center center;
    background-repeat: no-repeat;
    background-size: cover;
    opacity: 0.3;
}

Answer 9

and you can do that by simple code:

filter:alpha(opacity=30);
-moz-opacity:0.3;
-khtml-opacity: 0.3;
opacity: 0.3;