User blog comment:ShitaraRen/Upcoming Event?/@comment-1004812-20130416111525/@comment-1004812-20130416142736

Nnn, how'd I put it... It's game's version, not necessarily the date when the pic was shown/created. From its source, this came from a dated directory (/2013/04/2.27_Tower01.png) of their server.

...I'm probably delving in rather deep in the game's source or something. =x=;;