Pictures of the Shiratsuyu-class destroyers including all 7 of: Shiratsuyu, Shigure, Murasame, Yuudachi, Harusame, Samidare, Suzukaze. This pool exists because most artists leave out Samidare & Suzukaze (or sometimes Harusame), so finding an image with the full set is kind of special. Since the point of the pool is to gather images that include the oft-excluded sisters as part of the group, it may be alright to include an image where one of the usual ones is off-screen or something, even if that doesn't explicitly fit the description. Use your judgement.
Since this pool was created, the last three Shiratsuyu-class destroyers have been added to the game (Umikaze, Kawakaze and Yamakaze). Their presence is not required for a post to fit this pool, but Samidare and Suzukaze are required. This is not just "at least 7 of the class". It's possible another pool may be justified for all 10, but currently the tag search pool:10270 yamakaze_(kancolle) is pretty reliable and works for any user level.
Also, this pool is specifically for pictures that focus on the Shiratsuyu class. Other characters being present is okay, but pictures of everyone don't belong here.