Kit Harrington, who insisted all summer long that Jon Snow was dead, was spotted filming on the set of Game of Thrones' sixth season. But what's more intriguing than the fact that Jon Snow is alive, is the fact that he isn't wearing the black of the Night's Watch.
Snow has apparently traded in his Night's Watch armor for that of the Starks, suggesting that Snow will forsake his Watch brothers and reclaim his Stark heritage. That would fall perfectly in line with the expected flashback to the Tower of Joy, which will hopefully reveal who Jon's true parents are. And if Snow leaves the Watch, it would allow him to rally the remaining Stark loyalists in a battle against the Boltons, who are currently ruling over the North from Jon's family home Winterfell.
As to how Jon Snow rises from the dead, it's speculated that the woman under the umbrella in the photo is Carice Van Houten, who plays the powerful priestess Melissandre. The Red Woman became very interested in Snow last season, and it's not much of a stretch to believe that she would resurrect Snow under the assumption he may be the prophesized Azor Ahai.