In this picture, the scapula are pulled together, toward the midline. Many people habitually exercise with their scapula in this position. This is sometimes a hold-over from the old military, "chest out, shoulders back" attitude. However, it is better to have enough body awareness to make choices and use a more neutral position where it is appropriate.
There are times in exercise -- certain weight lifting and yoga moves come to mind -- when there is such an expansive opening of the chest that the shoulder blades are brought closer together in the back. This is a little more integrative and supported than independently sliding the scapula together.
