jQuery index finding

jQuery index finding

<div class="es-carousel">
<ul>
<li><a><img src="something157.jpg" ></a></li>
<li><img src="blabla.jpg"></a></li>
<li><img src="nonsense.jpg"></a></li>
<li><img src="cthulhu.jpg"></a></li>
</ul>
</div>
The html is above.
The jQuery selector I have for finding the img with the right src:
$(".es-carousel").find("ul li a img[src*='something']")
The problem is I need to find the index of the li that this image is in.
(I plan on use .index() for that) I have no idea how to select that
precise li which has that image.
Can anyone show me the right direction or give me an idea? All help is
appreciated.