It's a perfectly valid question, coastwatcher, and it is asked from time to time.
It is important to remember that ShipSpotting is not a top-down single collection of photos of ships, selected by Admin; rather it is a platform for members to share their photos in their individual galleries, and to enjoy each others' images, along with the general public. Members motivations for posting more or fewer images vary, and the flexibility of the site allows for all to be accommodated, and I see no need to judge others' objectives, provided they do not impinge directly on other members.
The site has a small number of "site standards" to try to ensure that all images are of good quality or better and maintain a focus on the depiction of ships themselves.
http://www.shipspotting.com/support/faq.php?category=Site%20standards%20for%20photosAmongst these is
12. Multiple photos: When posting multiple photos of the same vessel taken on the same Date, the submission must be restricted to a maximum of 4 photographs with a significant change of Aspect/Angle between the photographs. The Photo Admin try their best to ensure that this respected, but it remains a matter of judgement, and I am sure that we miss some where the difference is too small.
Our hope is that all members and visitors find what they want to see, and that they are not too bothered about repeated views of the same ship, whether by the same photographer of different, and just pass on to something more pleasing. For the record, we have been assured that the total number of images is not a problem from a resource point of view - if that were to change, we would of course consider how best to respond.