I think one of these men may be my great great grandfather, Richard Williams, who was a stone mason in Caernarfonshire. It's the size of a cabinet card. There's nothing on the back except "Taid" (grandfather) and the small stamp also attached. It came from a set of photos left to my mum, so I'm not sure whose taid he is. Richard was baptised in 1828, but I don't if that helps to confirm whether it's him.
Also, if someone could improve the contrast and clean it up, I would be extremely grateful, because whoever it is, I really like the photo. Thank you.