Received outstanding support help in creating static headers for pages in the Atahualpa theme.
One last detail . . . there are 7 menu items on the site - 6 are pages and one is a category. In the css code the pages have codes that are express as:

body.page-id-4 div#my-imagecontainer {
background: url('http://www.clbengineers.com/wp-content/uploads/2012/09/WaterPlantHeader-for-pages.jpg') top center no-repeat;
}

However, for the category page I entered this code and I am sure I have not identified the category in proper css.

body.page-cat-3 div#my-imagecontainer {
background: url('http://www.clbengineers.com/wp-content/uploads/2012/09/RefineryPageHeader.jpg') top center no-repeat;
}

could I please get one last bit of help in writing this category code properly?
Thanks,
Westpro

If you look at the source code and search for "body class" (without the quotes) you will see there are several classes you could use depending on what you want to affect.
It could be

body.archive div#my-imagecontainer

or

body.category div#my-imagecontainer

or

body.category-projects div#my-imagecontainer

or

body.category-3 div#my-imagecontainer

Perfect! Thank you!