How to add a class suffix to position gkHeader or gkBg

I am trying to add a class suffix to the gkHeader or gkBg so that I can set up a different background image for certain pages. I added a class to the menu and tried to specifically insert an image via css however it seems as if the classes are being applied deeper into the stylesheet cascade and it's not actually applying to the header. Any ideas on how I could manually set a class for each header as opposed to just an article page?

I also thought that maybe adding a custom HTML Module with a fixed position would assist with this but I was unsuccessful.

There is no way to add suffix for this elements and you should use suffix for whole page, you to do it you can find here → http://www.gavick.com/documentation/joomla-templates/customizing-joomla-template/how-to-use-different-background-images-on-different-pages/

In this tutorial you will find complete step by step instructions how to change background based on page suffix.

Thank you. I ended up getting the HD-BG module from the JED as you advised. This actually ending up working perfectly once I made the necessary css modifications.

Ok but suffix for pages may be useful in your future modification because it allows you to provide different styling for every single page.

Ok but suffix for pages may be useful in your future modification because it allows you to provide different styling for every single page.

You're right it does. I also used the suffix modification as well but I had forgot to mention it here.