div, img and table problem

[ja1977]

i have a problem with that i am trying to put a div on top og an img that
are inside a <td>....

The problem is that if i set the div style to absolute, the div stayes the
same place no matter how big the browser is. And if i chose style to
relative the div segment moves the image down... This is the code:

part of html:
<td colspan="11">
<div class="transparent" id="">
Content for class "transparent" Goes Here<br><br
</div>

<img src="images/udspil_14.jpg" width="805" height="477" alt="">
</td>

css:
.transparent {
position:relative;
filter:alpha(opacity=70);
top:-50px;
display:block;
width:638px;
height:438px;
color: #FFFFFF;

left: 0px;
z-index:2;

}