In order to utilize the correct SKINS variables, I converted this from templates/:

<a href="{$_entry.media_image_url}&amp;width=800&amp;1={$rand_id}" target="_blank" class="lightbox"><img src="{$_entry.media_image_url}&amp;width=160&amp;1={$rand_id}" width="160" alt="{$_entry.media_name}" class="i_outline"></a>


To this in skins/:

<a href="{$MEDIA_IMAGE_URL}&amp;width=800&amp;1={$rand_id}" target="_blank" class="lightbox"><img src="{$MEDIA_IMAGE_URL}&amp;width=160&amp;1={$rand_id}" width="160" alt="{$MEDIA_NAME}" class="i_outline"></a>

