Here's the scenario: I've uploaded an image to use as my custom header with Twenty Ten. All works as expected. If you click 'Restore Original Header Image' there's no apparent way to switch back to the previously uploaded header image.
Am I forced to delete the image from the Media Library and proceed with the header upload process to set it back as the header image?
It would be nice if there was an option to set an image from the Media Library as the custom header image.