Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

 The Oswald double on the right is definitely not him. He looks a lot like him, but there are distinct differences that I'll lay out. Oswald had longer hair, and he didn't have that deep recession on his right side like the double. And the double's deep recession may be artificial; his hair may have been removed there because recession and thinning usually go together, and his hair looks thick otherwise. 

Oswald had a longer nose with larger tip cartilage. He also had flared nostrils, unlike the double who had straight nostrils because there was no arch in his nasal tip, as Oswald had. So, the double's nose on the right was shorter and blunter. Oswald also had larger ears with a more expansive helix. 

Another big difference is that Oswald was thinner. He looks leaner than the double. You can see that the double's face was puffier. 

And Oswald's prominent sternocleidomastoid muscles on the left are apparent in many of his photos but not seen on the double. 

I am not denying the great likeness between them, and I wouldn't object to calling him a doppelganger. But, the double on the right is DEFINITELY not Oswald.