banner images

uwosh.thememain and uwosh.themecollege both look for a folder called "main-images" in your site.  If it finds one, it looks inside it for an image.  If it finds an image, that's what it will display in the space between the yellow audience nav and (in the case of uwosh.themecollege) the blue site title bar.  If more than one image exists in that folder, there is Javascript that randomly picks one of the images to display in that space, so you get the effect of rotating banner images on each page reload, if you choose to supply more than one image.

The other cool thing brought to you by Plone's "acquisition" feature (a form of inheritance, though sadly not the kind one would hope for from a rich uncle) is that Plone looks for the "main-images" folder at any level of the site.  For example you can have a different banner image (or a different set of rotating banner images) in every folder and subfolder of your site.  If your site's address is uwosh.edu/coolpeople, you should have at least one main-images folder at uwosh.edu/coolpeople/main-images but if you had a folder like uwosh.edu/coolpeople/family then it could have its own set of banner image(s) at uwosh.edu/coolpeople/family/main-images.

There is a particular size (especially width) that will work best.  Have a look at the images at uwosh.edu/home.  Personally I recommend using a shorter (less height) image so that more screen real estate is used to present real information rather than imagery.