XF 1.5 How to make an image responsive?


Active member
Hi all, I'm trying to create a help page with images but I can't get the images to go responsive.

I have this in my extra.css

.responsive-image {
width: 100%;
height: auto;
display: block;

And this is the html I'm using

<div class="responsive-image">
<a href="http://xxxxxxxxxx" target="_blank">
<img src="banners/xxxxxxxx.gif" alt="image logo">

Could someone please advise what I am doing wrong? Thanks. :)