I'm trying to use Nicolas Gallagher's brilliant CSS work on applying CSS drop-shadows to elements without images and without extra markup using the :before and :after pseudo-elements. His code is provided below...

.drop-shadow {
   position:relative;
   width:90%;
}

.drop-shadow:before,
.drop-shadow:after {
   content:"";
   position:absolute;
   z-index:-1;
   bottom:15px;
   left:10px;
   width:50%;
   height:20%;
   max-width:300px;
   -webkit-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
   -moz-box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
   box-shadow:0 15px 10px rgba(0, 0, 0, 0.7);
   -webkit-transform:rotate(-3deg);
   -moz-transform:rotate(-3deg);
   -o-transform:rotate(-3deg);
   transform:rotate(-3deg);
}

.drop-shadow:after{
   right:10px;
   left:auto;
   -webkit-transform:rotate(3deg);
   -moz-transform:rotate(3deg);
   -o-transform:rotate(3deg);
   transform:rotate(3deg);
 }

I'm trying to target all images wrapped with an a tag, which in Wordpress are really full-size images that have been resized to a medium height and width in the backend. When the user clicks on the smaller image in the post, it opens up a new tab with the fullsize view of the image (I'm sure you're already familiar with this if you use Wordpress). For some reason, I can't get his code to work, and I'm wondering if I'm targeting this wrong within my CSS. Can you help?

In place of the .drop-shadow class that he uses, I'm target all images wrapped with an a tag within the #main-i div. So, like this...

#main-i a img

Does anyone know how to target it better than I have so that I can get the drop shadows to be applied for all images within the specified div?

Thanks for your help!

P.S. An example of the image I am wanting to target with this CSS is the picture of the Haitian boy here: http://lifebridgecypress.org/our-heart/seventy-two/help-haiti