I had the same reaction at first! However, I checked over Getty and there are a TON of images of him with a bunch of HP actors. Admittedly, they could ALL be wrong? But, uh...

Unfortunately most of the other pics of him I was able to find were from 2-3 years ago. One can change a lot between the ages of 15 and 18. Maybe not this much? But I'm willing to believe it.