look n feel of portal

Dear experts

we are working on changing the look n feel of our portal .we want to add images as background for the various portal pages based on its content .

but when i try to add a image (customized a desktop )that image is reflecting on all the pages ..how can i restrict that image to a single page .

our requirement is to have a relavent image for every page .

is this possible?

points would be rewarded for useful

Regards

swetha pola