This sounds like the same problem my old employer faced some years ago when making the Star Trek CCG. Initially the game was licensed for just TNG, and the process of getting card images approved was (relatively) straightforward. Sometimes we picked from a Paramount-provided gallery, but increasingly we went to the episodes and pulled our own. The latter of course required individual image approvals from the licensing department, and that usually went pretty smoothly. (Fun fact, during that time our licensing liaison was Guy Vardaman, who also appeared on screen as Brent Spiner's photo double and in various roles such as recurring crewman Darien Wallace.)
After some initial success, we started adding other series to our license. I was overjoyed when we got TOS, but it came with some new legal hurdles, the worst of which was actor approval. Later series had used actor contracts that made it easier for Paramount (I think they could approve many things themselves, but had to consult actors in certain scenarios). But TOS was a whole different ball of wax, because the contracts back in the '60s naturally didn't anticipate all this future fandom and merchandising. Actors/estates had more control over their images, and in some cases getting responses back was difficult and slow. I remember a few times we had difficulty convincing Paramount to let us create cards for certain lower-profile characters when they had lost track of the performers/estates (it's possible we were the first licensee in years to want to publish a close-up shot of Romulan Guard #3 or whatever).
I believe this is the reason we see so many repetitive, uncanny-valley depictions of TOS characters in modern merch. There seems to be a standard set of illustrated main-character shots that are very lifelike and look
almost right, but are a bit off. Especially Kirk. I'm guessing Paramount may have been able to contend that these are artistic interpretations that do not require approval -- and thus they have a ready-to-go gallery of "royalty-free" or at least approval-free pics they can encourage the less picky business partners to use. If a licensee is happy with the same crew pictures as the other licensees are using on their card decks and standees and notebooks and stickers and heat-changing mugs, then they can already use them without further ado. I could be wrong, but for me it would explain the proliferation of these relatively modern images.