The four clips are titled Day 2, Day 220, Day 184, and Day 236. Each one features a person's photo pinned on a 'Missing' board, perhaps pertaining to characters introduced in the DLC.
Back in February, series writer Gary Whitta said "there may very well be more Walking Dead from Telltale before Season 2." Also, a Polygon report indicates at one point Telltale's exhibitor page on the E3 website listed 'Season 1 DLC' for The Walking Dead. While it's never safe to assume anything when it comes to the zombie apocalypse, chances are there are some more tough choices on the horizon.