Sci Fi characters and actors' images

Okay, taking Doctor Who as an example, I’m guessing that the BBC can use the images of the actors who played any of the Doctors, as they portrayed those particular characters, in any future episodes? For instance, in the “Five Doctors”, they had a First Doctor played by an actor who resembled the late William Hartnell. Could a computer generated Fourth Doctor (for instance) be dropped into a current episode whether Tom Baker hollers or not (doubt that he would)?

The same with the Star Trek remake. I know they tried to get the blessings of as many original actors as they could, but could they have a new Kirk with a pissed off Shatner?

If the contracts already in place stipulate they have the freedom to do so, yes. Usually a studio will have ownership rights to the character image so can do anything they want with them, providing they are still portraying the same character.

But contracts can vary, and there’s probably a statute of limitations that applies as well.