CSS: Pseudo-elements :before and :after inheriting width/height from original element

I am using the css pseudo elements :before and :after to give an indent-effect on some of my images on a website. However without specifying the width and height, these won't display. This would have me specifying a fixed width and height for each of the images, which I guess would work for a static webpage.

However because these images are generated dynamically with jQuery and are user submitted, images differ in width and height each time. Now I could probably can fix this with Javascript by getting the width from the image and passing it on to the :before, but this seems like it is too much work for something like this.

My question is if there is a way to do this with CSS only, to have the width of containing the image being passed on to the :before on this < li >, so that the :before and :after pseudo-elements inherit the width and height of the orginal element.

The basic page layout:

<ul>
   <li>
       <img src="foo" />
   </li>   
</ul>    

# css style simplefied
ul{ float:left; list-style:none}
li{float:left;}
li img{float:left}
li:before{
          content:"":
          position:relative;
          position:absolute;
          float:left;   
          box-shadow:0 1px 2px rgba(0,0,0,0.4);   

}

PS: compatibility needed is only for mobile Webkit browsers.

EDIT

I could for instance add lines to the CSS with Javascript by using the following lines:

var heightImg = (($('ul li:nth-child(n)').height())) + 'px';    
document.styleSheets[1].insertRule('ul li:before { height: ' +  heightImg+ '; }', 0);

But this would mean that I'll also have to work with dynamic id's. Which won't be hard, but I'm just wondering if there isn't a CSS only way.

Solution 1:

:before and :after pseudo-elements are inline boxes as much as I know. Therefore, using display: block; might help you.

Solution 2:

li{
    float:left;
    position:relative;
}
li img{
    float:left;
}
li:before{
    content:" ";
    position:absolute;
    width:100%;
    height:100%
    box-shadow:0 1px 2px rgba(0,0,0,0.4);
}

Solution 3:

it seems content:" ": is important along with display: block

Solution 4:

Try:

ul {
    position: relative;
}
li:before {
    content: '\00a0';
    display: block;
    float: left;
    position: absolute;
    height: 100%;
}

It's worked for me.