penders - 11:03 am on Sep 27, 2011 (gmt 0)
This is not what CSS is designed for and consequently CSS can't do what you require. background-image's yes; content no.
A separate PHP file could contain an (associative) array of images. You include this file on every page you require these images and reference the image as required. When you upload a new image you would update this 1 PHP file rather than your CSS. Would that be acceptable? You could later take this a step further and include your image URLs in a database, add a front end and you wouldn't need to manually edit any file.
$IMAGES = array (
'image1' => '/path/to/image1.jpg',
'image2' => '/path/to/image2.jpg',
'todays-weather' => '/path/to/todays_weather.jpg',
In your PHP page:
<?php include('image_list.php'); ?>
<h1>Hello welcome to</h1>
<img src="<?=$IMAGES['image1']?>" alt="">
<img src="<?=$IMAGES['todays-weather']?>" alt="">
Your $IMAGES array could contain a lot more information, such as width, height, description etc. and include a function that generates the entire IMG element for you.