Here is a resource I bet you didn't know about. In a binder at the right end of the counter in the Largo Library Genealogy Center are pictures of county court houses taken from old newspaper articles. They are organized by state and then by county. Not all of the court houses in the country are represented, of course, but you will find more than you would expect.
Ask the genealogy consultant at the desk to get the binder for you. You can then use your digital camera to take a picture or use the copier to reproduce the photo to take home for your files.
I'm not sure who put this collection together, but who ever it is deserves our thanks.