6.01 "Exile on Main Street"
Official episode description: "It's a year later and Dean has given up hunting and is living with Lisa and her son Ben. Mysteriously freed from his cage in hell, Sam finds Dean and tells him he need to rejoin the fight and introduces Dean to a world -- a family -- he never even knew existed: the Campbells, his mother's family, lead by none other than their Grandfather Samuel."
THE FIRST STILL RELEASED WAS POSTED
HERE source:
tvsquad,
spnsite IN HQ HERE omg sammy's grin while they're hugging :3