Image rendering Firefox vs IE

Hi, i'm not sure if CSS is the best section to post this but i'm looking for a css solution, that's why i posted here.

I have a website with a big image as background and it's resized to fit the browsers window, the problem is that it looks awful in IE while it's fine in firefox..

Searching around i found that the default rendering mode of IE has lower qualitty than FF, so changed that with css as follows and things improved a bit.

image-rendering: optimizeQuality; /* Firefox 3.6 */
-ms-interpolation-mode: bicubic; /* Internet Explorer 7.0+ */

But still it looks much better in firefox, so i am wondering if there is something else i'm missing..

The site is www.gastongreco.com so you can see for yourselft

Thanks in advance!

 

Fixed
There was an error in my css and the abobe declaration was not working..

 

Use this script

http://www.twinhelix.com/css/iepngfix/

 

That script allows the use of transparent PNG files in IE 5... That's not what i was talking about

 

But your site has that problem!! Look at email picture by IE6.

 

Ouch! lol
Will check browser stats.. i'm not a big fan of that kind of fixes, thanks for letting me know