This episode's Vaudeville Afterpiece is titled "The Mountain Climber."
When Gracie meets Bob Collins, she tells him he looks "very familiar". Robert Cummings played himself in season 5's Gracie Thinks Bob Cummings Is in Love with Her (1954).
When the photographer reveals himself, it turns out to be Bob Cummings. This was an in-joke at the time, because Bob was starring as a photographer on the1950s' sitcom "Love That Bob" (a.k.a. "The Bob Cummings Show"), which is why Gracie says he looks familiar.