Forget about arms and chest shapes. sometimes Too much information blurs your judgment. Just focus on the face.
1.a photograph claiming to be Madonna in 1979
2. Real Madonna Photography from 1978
The person in the 1979 photo may or may not be Madonna. However, if you cut off the upper body of the person in the photo and look at the face, you will change your mind again. If you didn't look at the photo that showed the person's chest first, you could argue whether it was a man or a woman.
But if you look at a photo from 1978, just a year ago, even if the upper body was cut off and the top half of the head was cut off, but at first sight you clearly can know that's Madonna.
My biggest problem is that I see her famous upper lip beauty mark even though the 1978 photo was taken by a little bit more next to her face than the 1979 photo, but why can't I see it in the 1979 photo.
It maybe Madonna but I have to agree with people that it more like 2005 confession era middle aged madonna