I must admit I do find those bathroom mirror shots to be the least attractive way to have your own picture taken. Regardless of the condition of the bathroom itself, though messy clutter does distract my eye from the subject, even if I really can't determine the actual cleanliness of the room.
For my own verification pic I simply used the camera's self-timer. All the rest of the RJ pics of me (which are private) were taken by others, no mirror shots. Because another problem is that your image is reversed, and people can really look different in real life than from the reverse mirror view, since the features of most faces are asymmetrical.
And if you want to crop the self-timed pic, to eliminate the face or other features, then use computer editing software, which is very easy for doing a simple crop. No need to use a mirror to compose the shot perfectly in the camera, you can afford to be a little imprecise using the self-timer if you edit afterwards.