The problem with many of the site categories is that they no longer reflect today's modern, multi-purpose shipping, and the descriptors used in to day's shipping industry. This just leads to confusion at time amongst members, as to which is the correct category for their photograph. This particularly applies to offshore vessels, which, due to modules that can be added or removed easily, may operate in different vessel categories on different voyages or charters. Many tankers are now equally capable of carrying crude oil, products and chemicals, and frequently do on back to back voyages to avoid ballast voyages. There is no category for con-ro's etc. It seems the same applies to some of the smaller passenger vessels.
However, there is no easy answer for this site, with over 2.5m photographs posted, it's too big a job to review those already posted, and would be too confusing to introduce new categories. The mistake was made at the outset, in trying to make the categories too narrow, but, unless someone is going to volunteer to undertake a review, I guess we're stuck with it.