Commons provides consistently named categories with basic information on vessels, many of which don't have Wikipedia articles yet. Several "by" subcategories of Category:Ships allow to find vessels (and images of vessels) with different criteria.
Participants aim to identify ships by name (20,000 by now), year of completion (97%), flag, type/function, IMO or ENI, country of construction (58%), etc. The 20,000 categories include ca. 100,000 images in their main category. 33% of these images are used at Wikipedia.
Wikimedia Commons now has over 15 million files as of December 4, 2012. 17W Aug 14 1996 0124Z.png is a file depicting Tropical Depression Seventeen-W on August 14, 1996 is a candidate to be the 15,000,000th file.
The actual file is often difficult to identify due to the fact that many files are loaded at almost the same time, and that a number need to be deleted to maintain the integrity of the repository. This image was created by the National Oceanic and Atmospheric Administration (NOAA) in the United States.
Wikimedia Commons is multilingual. Use Babel in order to find contributors who speak your language. Please add information about the languages you understand to your user page. The language policy is discussed at Commons talk:Language policy.
All help, project, maintenance, discussion, policy pages and further tutorials about how to work in wikis like Wikimedia Commons are listed there. For an overview over the structure of the Wikimedia Commons project itself see Category:Commons.
Tools for uploading and further maintenance of Wikimedia Commons as for example Commonist for uploading large numbers of images. Tool integration helps you add functionality to your Wikimedia Commons web interface.
Overview on how to embed Wikimedia Commons content into various Wikimedia wikis and how to reuse Commons' content by third parties. See also the media help for software and hints how to watch images and films and listen to audio files provided by Wikimedia Commons. See Featured pictures, Valued images, Picture of the day and Media of the day for particularly valuable content you can reuse.