I would be careful regarding asking members to provide too much detail, however frustrating that might be for some members. Not all members who post photographs are interested in such detail, they like good and post good photographs of ships, but the finer points of a vessels details are not things that they want to get involved with. Start making it more involved to post photographs could well deter such members from posting photographs that would otherwise be an asset to the site.
From my point of view, the IMO# is sufficient, if I want to know more there are plenty of sources for me to use.
We are frequently told when debates occur, that the site is primarily a site for ship photographs, not a database of ships. It should stay that way.