Hello all,
I would like to set a background image for four pages within my site, which includes 16 pages. Any help on coding this in the CSS is greatly appreciated.

Thanks,
Brian

the background is applied to the body so define the one for the most pages at ATO->Body, Text & Links->Body Style, and then add this at ATO->HTML/CSS Inserts->CSS Inserts (NOTE the page id can be found by editing the page and then looking at the address in the browser address area, the last number is the page id)

body.page-id-5, 
body.page-id-7, 
body.page-id-9, 
body.page-id-22 {
background: url(http://yourdomain.com/wp-content/themes/atahualpa344/images/backgr.gif)
}