Displaying Images on Page with CSS

Hi,

I've been learning HTML & CSS on and off for a few weeks. I'm having trouble getting some images/buttons to display on my site:

http://jakestubbs.co.uk/

It's the 'monsters' at the bottom, you'll see what I'm talking about. The images don't adjust when the browser window is re-sized and they appear differently on different resolutions.

I'm currently using this code in the CSS:

Code:

#twitter-logo {
    background-image:url('images/twitter.png');
    display:block;
    height:128px;
    width:128px;
    position: relative;
    top: 426px;
    left: 710px;
}

And this in HTML:

Code:

<a href="http://twitter.com/jakestubbz" title="Twitter" id="twitter-logo" />

I'd appreciate any advise anyone can give!

Thanks.

 

Thanks, for the quick reply. If I do that though - on say my 13" MBP and get it so it appears correctly and then load the page on a screen with a different resolution they'll be in the wrong place and vice versa...

Hope that makes sense.