Newbie Question - How to Change Images on Page Headings

[ConfusedTim]

Sorry this is a basic question but the guy who did our CMS development  is no longer available to help me.

I need to change the images at the top of our web site pages (e.g on this page where the CMS made simple logo plus CMS Geek Moot advert is) is and dont know how to do it.  Do i change the image in a template/CSS or other place? Is there a set of basic steps i could follow to make thses changes?

Thanks for your help

[Dr.CSS]

It all depends, I use CSS to fill boxes with images others put it right in the template, w/o a link or some code it is impossible to tell you how...

And cmsms version, system info, etc. is always helpful...