Site not showing well with IE7

Hi,

I’ve tested my site and it looks well with IE8, FF, Opera, Safari & Chrome.
It doesn’t look well, however, on IE7.
There are several images in the header and they’re supposed to be presented next to each other. But in IE7 they’re presented on top of each other.
Here’s a sample of the header code:

<a href="https://shnizak.com/?????/"><img src="https://shnizak.com/wp-content/themes/High_Speed/images/nataliface-bw.PNG" alt="" class="nataliface-bw"/></a>
<a href="https://shnizak.com/?????-????/"><img src="https://shnizak.com/wp-content/themes/High_Speed/images/makeup-bw.PNG" alt="" class="makeup-bw"/></a>

And here are the defining classes in style.css:

img.nataliface-bw {
	position: absolute;
 	margin: 0px 0px 0px 0px;
	left: 0;
	top: 0;
        z-index: 10;
	}
img.makeup-bw {
	position: absolute;
 	margin: 0px 0px 0px 125px;
	left: 0;
	top: 0;
        z-index: 10;
	}

Can anyone say why it’s wrong with IE7?