^ The latter. For instance, the guy who played "Lobot," as you put it, probably signed a general release for the use of his likeness in connection with the property.
A more established actor such as Paul Winfield might have had a clause in his contract that gave him more control over the use of his likeness from stills and production photos taken on the set of Star Trek II. Or maybe he gave a blanket release. It varies.
But the photo of him from an earlier era, on a different show or movie, belongs to whatever entity either produced it or bought out the rights to that image. Simon & Schuster can't use it as a photo reference for Paul Winfield's likeness on a Star Trek book or comic book unless they first secure permission from the copyright owner of the photo, and then, depending on what rights Mr. Winfield or his estate granted to the copyright owner, they might need to obtain permission from the estate of Paul Winfield to use that likeness for commercial purposes — a negotiation that is also likely to cost money.
The principal cast of the various Star Trek series have varying degrees of control over their likeness in the books, comics, and other licensed materials. Some have more, some have less, others have none. A few have pre-approved a limited selection of images in the CBS photo library for such use. Others insist on vetting every use. And so on.