Oswald in the doorway: the blog of the Oswald Innocence Campaign, by Ralph Cinque

OK, so here is the CBS Evening News on Nov 22 with Walter Cronkite, and he opens with the Altgens photo. Be aware that assassination coverage continued from 5:30 to 6:30, although Cronkite got a break. It featured other newsmen. But, they didn't show this. 

https://www.youtube.com/watch?v=U0b92Fc8WZI

Odds are great that they got that to Cronkite very soon before that. They wouldn't have sat on it. If they had it an hour before, they would have shown it an hour before. It was 6:30 Eastern, hence 5:30 Central, hence, it took exactly 5 hours to make the Altgens photo presentable to the public.