Here is how I would do it.
Suppose your HTML looked like this:
<div id="myDiv">
<img src="myImg.jpg />
</div>
Your CSS should look like this: (remove style tags if using stylesheet)
<style>
#myDiv
{
width: 804px;
height: 100px;
position: relative;
}
#myDiv img {
width: 500px;
height: 70px;
position: absolute;
bottom: 0px;
left: 152px;
}
</style>
By placing the "position: relative" definition in your div, the div becomes the reference point for child elements, such as your image. You may then "absolutely position" the image, 0 pixels from the bottom, and 152 pixels from the left.
Let me know if this helps.