In attempting to revise the header, I've ended up with just a caption. I probably have extra stuff in the code that is the cause, but don't know enough to tell where the error is.
In the custom header settings page everything looks correct, but when viewing the page, only the text appears. I've deleted any previous files that were uploaded for headers, and have only the one in the media library files now. I used the remove image and reset image functions in a attempt to clear it out, but the result is the same.