Drupal 7 - field template - $item - img tag
I usually use Devel module to figure out things like this. Install and enable Devel, then add something like this to your field template file:

&lt;?php kpr($item); ?&gt;


This will show you all the contents of $item (arrays and objects). Then you can just print the part that you want (the img tag in this case), wrapped in the extra class.