I'd like to remove my current Twitter avatar and have it revert to one of the default avatars/profile images.
How do I do this?
Delete this image.
This is not possible anymore without re-uploading the original Twitter Egg image.
From Twitter Support (DM):
Alex, there is no longer an option to delete - you must upload a new photo to replace the old one.
22 Aug at 22:21
Update 02/06/2012: This is now possible again.
And the result: