The dclsg fan who shared this picture did not say when this was taken, but I read a fan account from her on May 23, so I think this was taken on that day. 😛
This was taken by another fan on the same day, which was also the day of the 2nd fan event. And this seems to be the original of the photos posted here.
The fan also spotted a staff’s script autographed by SeungGi: