Wikimedia Commons is a media repository that is created and maintained by volunteers around the world. It is multilingual, free to use and its contents is free to share and reuse, even for commercial ends. Images uploaded on Commons can be used in any Wikimedia project, including Wikipedia, by simply using wiki markup ([[:Image:Name of image.ext]]).
Being a media repository, and following the spirit of hosting only contents free to share and reuse, Commons does not accept media under a fair use rationale. It does, however, accept and host media that may be perceived by some as partial or offensive; see our general disclaimer.
Whereas Commons itself is a project where collaborators should strive to keep a neutral point of view (NPOV) in rising issues, such as the interpretation of copyright laws, evaluation of quality and featured content, and general interaction with the community, hosted media itself does not have to follow such NPOV. Indeed, images perceived as offensive or distasteful to some (such as those depicting sexual contents) can be used, e.g., in the context of Wikipedia articles about sexuality; sound files of racist speeches can be useful in history books in Wikibooks, and so on.
The fact that Commons is a multicultural wiki, where people from all over the world, having conflicting opinions and thoughts about issues such as politics or religion, edit and contribute to, can potentially lead to arguments about how media is represented and organized within the project, through its inclusion in gallery pages and its categorization.
It is important to add concise and objective descriptions to images. Please avoid using peacock terms when doing so. It's fine to add the occasional comment, such as "a beautiful sunset", "a charming street" - this is a graphic project after all, and aesthetics are an intrinsic part of it. It's also fine to describe things adjectively whenever necessary: "the largest river in the world", "the most populous city in South America", etc. Remember that Commons has a project scope, and that we are focused on contents, not how great your images are.
Please give proper names to images. Not only they should be non-cryptic, they should be objective. The more neutral and informative an image name is, the better.
Categorization can be a hot topic on Commons, for different reasons. One difficulty arises from the fact that due to technical limitations, all categories must be in English. This can be perceived by non-English speakers as a bias towards the use of English on Commons. That is not the case. Where appropriate, local terms in other languages are also used.
Categories should not be biased towards personal, religious, political or other non-neutral views. They are simply ways of organizing pages and media, and their names should reflect their contents in a neutral point of view. It is of course allowed to have categories about controversial issues, but categories themselves should not be controversial.
For example, it's fine having a category about heresy when its subjects are consensually considered depicting heretic acts; but it's unacceptable to add people's photos to that category because you think that they are heretic.
Another example: there is a category named massacres. It would be unappropriated to create a parallel category or subcategory named "Especially dreadful massacres", because that is a subjective view.
Exceptions are always tolerated - but use consensus as a base for deciding how to categorize.
Pornography and eroticism
See also: Commons:Nudity
Commons hosts some images that have sexual contents or make innuendos. Some have very explicit contents, while others depict nudity in more discreet ways. Commons is not censored and some images in this category are needed to illustrate concepts such as nudity, pornography, sexual behaviour and anatomy. However, these images with sexual contents are constantly monitored to ensure we keep only useful and high-quality material.