There is actually a reason for this photo reuse - during 67/68, the MLBPA was taking control of the licensing for baseball cards via a photo boycott. Topps had the rights to print the cards due to previously-signed contracts, but the players refused to pose for new photos. So in many cases, earlier photos were used.
That also explains why some teams, like the Red Sox, did not have Topps team cards in 1968.
https://sabrbaseballcards.blog/2017/...cott-of-topps/