While the origin of the leak is unclear, the artwork features all characters confirmed in the latest trailer accurate to their new designs. That includes Kimberly, who is teased at the very end of the trailer. One character, Mariza, also appeared on a billboard in the trailer.
Furthermore, if you zoom in far enough on one of the officially released screenshots, several unannounced characters can be seen listed on a tournament bracket, including Zangief, Guile, Dhalsim, Cammy, E. Honda, and Juri—all of whom appear in the leak.
Another character, Kanon (or Manon—the quality of the image makes it difficult to determine), also appears on the bracket, but not in the leak, suggesting the leak may be missing some fighters. The leak includes three rows of characters—eight, six, and eight—so it is possible two characters may be missing from the second row.
Here are the leaked images:
—From left to right: Ryu, Ken, Zangief, Dhalsim, E. Honda, Blanca, Guile, Chun-Li.
—From left to right: Cammy, Dee Jay, Rashid, Juri, Ed, Akuma.
—From left to right: Luke (U.S.A.), Marisa (Italy), Jamie (Hong Kong), Mimi (France), Lily (Mexico), JP (Russia), Kimberly (U.S.A.), A.K.I. (China).