This is a common mistake in genealogy. I lost the link, but there was a scientific paper about how few facial characteristics are out there to make relying on photos to prove or disprove a relationship meaningless. It’s pretty common in social media groups to say is person A related to person B? There’s a photographer – Do You Have a Look-alike? Find Your Doppelgänger – FamilySearch November 20, 2019 who on trips looks for fake twins. People who look like each other, but aren’t related in the last 40 – 200+ generations. Likewise, I have seen people try to claim they aren’t related to someone because they don’t look anything like the person in question. It’s worth noting in the link above, the following comment:
However, these odds apply only if we are being exact about the measurements of a person’s facial features. The thing is, our brains don’t work like algorithmic facial recognition software; we don’t look at someone’s facial features in isolation from one another. Instead, our minds recognize people’s faces as a “sum of parts”—that is, we take in the whole face at once and don’t get caught up in millimeter measurements of someone’s ears or nose.
A good example of why not to use photos. There are some characteristics that tend to run in a family. Just because you have the characteristic and your suspected relative has the same characteristic doesn’t mean you are related. You can be related to another family who also has the same characteristic who isn’t closely related to the other individual. I would take it a step more if you have and person B have several unusual characteristics in common. That doesn’t mean you are related. It just means that your ancestors had the same sets of unusual characteristics as the other individual’s ancestors.
The sad thing is most “experts” don’t bother to address the issue at all, or they downplay it. No doubt some of them believe you can rely on photos to prove or disprove relationships. Others aren’t willing to go there as they know they won’t be listened to. I have been mistaken for numerous people over the years or had someone think I was related to someone they knew.
I had some stranger come up to me years ago and shake my hand. He thought I was John Doe (don’t remember the name he used) who worked at a local mall. He was close friends with this guy so it’s not like it was someone he knew only in passing. For him to mistake me as his friend goes to show how easy it is to make a bad assumption. In my case, I have a distinctive scar on my neck due to a car wreck. It’s hidden by my beard now, but it was visible when I was clean shaven. This was the result of a car wreck in 1986 so it’s not a birth mark or something that another person would probably have in the same shape and location.