php code in Event Display Builder

Hi,

I am trying to include a thumbnail image to the list like this.

<div>
<img src="<?php bloginfo('stylesheet_directory')?>/img/icon/feed-3.jpg">
</div>
<div>
<ul>
<li class="gce-list-event gce-tooltip-event">[event-title]</li>
<li><span>Starts:</span> [start-time]</li>
<li><span>Ends:</span> [end-date] - [end-time]</li>
<div class="btn btn-info">[link newwindow="true"]More details...[/link]</div>
</ul>
</div>

but the php code seems to be deleted once I hit save. Are there rules I need to be aware of to use php code in the Event Display Builder, or is it not supported?

http://wordpress.org/plugins/google-calendar-events/