About background images

Dear sir,
i created 4 pages in CSS with only one style sheet.
all 4 page styles are same. i used background image for main content. now i need to know that, every page main content should be separate background images without changing the page style...!! (All 4 pages main content background images need to change)
How?
please guiide me..

Thanks

Hi

You need to change div id for every page and call the image for that id

Regards