There’s no denying the self exist, but there are two versions of it. One is the self that thinks it constantly needs, and the other is beyond the thought of needing because it’s beyond the thought of self.
When you ask the question of who is the image in the mirror, do it in the context of who is the one who feels. Naturally the surface answer would be I feel, but who is this I (self) that feels and how about the one that exist beyond the surface of any feeling. This is the self outside the realm of one’s thoughts. Seeing this is all dependent on how settled the mind becomes and it’ll determine if one is aware that beyond the thought of self there is no one there, at least not in the context that self is thought of.
So who is it that feels? Sure the self feels, but it’s just not in the context where one attaches to any of their feelings. The thought of self and the self that exist beyond thought occupy the same form, they just exist totally separate from each other. They are as different as night and day as are the results of how one lives their life. One exist in the realm of attachment (thought). This is the self who most people think they are. The other self needs no label, there is existence, there just isn’t attachment to it. Find the self which brings the most benefit to life, beyond thought and the self without attachment will be revealed. This is the true essence of who you are, that is unless of course your thought of self is who you think you truly are.