[kh99]

This page tells basically how to do it: http://gfycat.com/about

You need to add some javascript to the page. The page you linked to appears to have it added to the end of the header template. If you want to use a plugin to do it instead, you could use hook location parse_templates and add it to the headinclude_javascript template hook, maybe like:

PHP Code:

$template_hook['headinclude_javascript'] .= " <script>
 (function(d, t) {
    var g = d.createElement(t),
        s = d.getElementsByTagName(t)[0];
    g.src = 'http://assets.gfycat.com/js/gfyajax-0.517d.js';
    s.parentNode.insertBefore(g, s);
}(document, 'script'));
</script> "; 


then you can create a custom bbcode, and the replacement would be

<img class="gfyitem" data-id="{param}" />