Some publicity photos seem to be clear to use; others don't.
I have a screencap from the 1960s (1964) that I believe may fall under fair use. I have that already mentioned "shopped" version of another image that also may fall under fair use, but I have no date for it. (It IS from a few decades ago, and being altered from the original may - MAY - be covered by fair use because of age. I'm not sure.)
Mostly a low-quality screencap is allowable under fair use, when there is no free version available, so long as a disclaimer is included. But - I'm not a copyright lawyer, and can only go by what I have been advised falls under fair use. (The lawyers I know do not work in copyright, so I usually proceed with caution.)