An announcement will be made on a new webpage that Square Enix has set up for this Thursday. The image on the site features two monster like sprites as well as sprite that resemble heroes from past Final Fantasy games.
Siliconera has concluded that the enemy spire is none other then the Behemoth from FFVI, but one of the sprites on the right looks like Bartz from FFV. We may be getting a port of FFV or FFVI for iOS since SE has said they would indeed be interested in porting it. Still it would be interesting to see a remake of a FFV similar to FFIII and FFIV following the remake trend but this time on the 3DS.
This announcement will be made this Thursday and the real answer to the images will be made clear then. The exact time for the news to be made is unknown but we will be sure to report on it as soon as information is known.