Sometime in the last month, my header image disappeared and was replaced by another one. I cannot find the image I was using, a blue tech/data looking banner. Now I have an image of a raspberry. I have looked through all the directories. There are 3 images in my images/header directory, none of which are the original. Any idea what may have happened? Can I get that image back from somewhere? I liked it.

My guess is that you did an automatic upgrade of the theme. When you do that WordPress deletes the contents of the theme folder and install the conteents of the theme in it. This would repopulate the header folder with the original three images.

You will need to find a backup of your original image...You did do a backup of the site (database and folders) before doing a backup...right?

Yes, I've got a backup from a couple months ago. That should work. Thank you.