different backgrounds in wordpress pages

https://codex.www.ads-software.com/Conditional_Tags#A_PAGE_Page

Elliot Jay Stocks had a post on this sometime back. Scour the web for that. You can hack with CSS, a bunch of jpegs and a little code in the header.

Something like:

<?php if (have_posts()) : while (have_posts()) : the_post(); ?>
<?php if(is_page('foo')) $page_style='foo';
elseif((is_page('bar')) $page_style='bar';
else $page_style='';
?>
<div <?php post_class($page_style); ?>>

should work and generate page specific classes that can then be used to style the background via CSS.