100% width image in hero unit

I'm looking to place an image inside the .hero-unit that takes up 100% of the unit. This means that it would scale according to the overal window size.

Right now i have the in there, but it looks like there's 100px padding to the right of the image. If i adjust the image max-width: 100% to something larger, it does not scale accordingly.

<div class="hero-unit">
    <img src="images/landscape.png">
</div>

Does anyone have an idea of how to remove the padding on the right, but also preserve the auto-resizing capabilities of bootstrap?