This is a photo I have not seen before used to illustrate a not very interesting website. The late Brian Pohanka shared with me his great collection of McClellan CDVs and this pose - almost a three quarter view - does not match anything therein. In its dimensions (unless it has been cropped) it is likely not a CDV at all.
I notice a moire pattern in the background that suggests the fine screen used in book publishing - or is this an illusion?
And the big, fat thumprint on his cheek - very distinctive.
Clues welcome - send them along.