Beej

WordPress 3.0+ is great. It shows you your uploaded header images. 
It’s too bad it doesn’t let you delete them as well! 
The answer is here with a simple yet extremely useful little plugin called Delete Custom Header. 
Unlike WP’s “Remove Header” button, this plugin completely removes the header image data 
from the database and the files from the server.
For themes with a header option, like Twenty Ten, Twenty Eleven, etc.

Delete Custom Header

Delete uploaded header images and remove them from the database.

Andy Fragen

Remove default header images and load custom header images from ‘The Headers’ page. Allows for easy selection of random header images in your theme.
A plugin that should be able to remove default headers for a theme and add custom headers based upon the article written by <a href="http://juliobiason.net/2011/10/25/twentyeleven-with-easy-rotating-header-images/" rel="nofollow ugc">Julio Biason</a> who was inspired by <a href="http://wpti.ps/?p=107" rel="nofollow ugc">wpti.ps</a>.
Create a Page named The Headers. Then upload header images (media files) to the the page. The page may have a visibility of private. All images displayed on the page will be parsed, those attached to the page and those added via image blocks.
Once the custom header images are loaded, just go to <code>Appearance > Header</code> or <code>Customize > Header Image</code> and select <code>Randomize suggested headers</code>.
The plugin will display an error notice if there is not a page titled, The Headers.

Add Custom Header Images

Remove default header images and load custom header images from 'The Headers' page. Allows for easy selection of random header images in your theme.

Delete Custom Header vs Add Custom Header Images