The tiny star cluster you see at the center of the field of view is another globular cluster. You have seen pictures of more prominent members of this class of galactic objects on my page, so the reason why this object appears so tiny may have two reasons: The absolute magnitude or the distance. The distance estimate of 33000 light-years actually reveals that the cluster is rather at the opposite end of our milky way. However, the size is also just about half of the showcase cluster M13, which is about 25000 light-years away. So it is all of it, size, distance and also the location close to the band of the milky way with all that dust and stars that makes for M56's rather humble appearance.