The poster Shiratsuyu's standing under is a take off Flags of our Fathers , the flag over Kuma's head is the maritime signal flag for Z, and of course the logo on the wall behind Suzukaze/Kinugasa is that of Kancolle itself. Don't know the small ones on the first floor or the one by Hiei.
I added an artist_request because the image doesn't contain an artist tag and there also doesn't seem to exist an artist tag for this artist.
I'm not sure if the pixiv-name that is shown in the source field should be used or something else (because looking at other artist tags sometimes it's the same, but sometimes also different).