Change icon of warn of new post/threads

[Zoiter7]

Square theme templates >> Forum Display Templates >> forumdisplay_thread_gotounread

Thanks! 
Can you help with the html?  I can't put a image on the start. Is a wrong use in html

<a href="{$thread['newpostlink']}" class="effect"><i style="font-size: 14px;"  alt="{$lang->goto_first_unread}" title="{$lang->goto_first_unread}" <img src="/new.gif"></i></a>