This is an essay. It expresses the opinions and ideas of some Wikimedians but may not have wide support. This is not policy on Meta, but it may be a policy or guideline on other Wikimedia projects. Feel free to update this page as needed, or use the discussion page to propose major changes.
whether there is a limit to the number of similar images, each potentially educational if it were the only one available, it is appropriate to host on a topic. Is the ten thousandth freely-licensed images of an adorable kitten educational? It is generally felt that "one image per topic" is too strict (a gallery of media per topic is instructive and useful for remixers, especially as we add nuance and subtopics over time), and that importing the unabridged corpus of freely licensed images on Flickr is too liberal. (lots of bad, fuzzy, non-illustrative photos, lots of redundancy, no curation)
when intentionally shocking a reader is appropriate. Some larger projects have a principle of minimal shocking - use the least shocking image that effectively depicts a topic. (should a shocking depiction of a decapitation be used when clear non-shocking images are available? is a powerful animated gif, that appears at first to be a static image ["focus on the two gray dots"] and frightens the viewer, necessary to illustrate the meme? Is the goatse image necessary to illustrate its article? &c.)
what constitutes grounds for removing/self-censoring images. (anything illegal in the US is clearly out. what about images that are likely illegal without a convincing explanation for their legality? [e.g., a series of professional studio photos claimed as 'own work' by an otherwise inexperienced photographer] what about material illegal in one region but not another? should legal standards of other countries be considered? should The Gambia be able to pass legislation that affects what Commons is willing to host?)
what level of care is required for licensing and personal image rights. (is an OTRS email required for all images of people? is copyright registration with a third-party service ever required? is this a moral issue, or merely a legal one? should the union of moral-rights legislation from all countries be considered... if a subject of a photo complains, when should that be considered above and beyond legal obligations... how much more care should be taken with images that could harm living people?)