Getting true X,Y on responsive input type=image click

I'm trying to make a form input type=image responsive. I want to get the true X,Y of original image, even if image was resized with a responsive design. For example:

<form>
<input type=image src=http://i.imgur.com/Ls5vGUy.jpg style="max-width: 100%">
</form>

I assume a jquery solution, but searching for with keywords ( input image responsive ) has not been successful.

Does anyone have a solution? I'm hoping there is a relatively simple one.