Wikipedia:Image citation

What is this for?
Note: Before reading too far, you may want to view the mock-up in order to picture what is being described here.

Current situation
Presently, images displayed in Wikipedia articles are, as a practice, not cited in the article itself. Captions are optional, but should cover the image's subject matter when included, and may sometimes include further information about the author, title, date, or source. The main purpose behind captions is to be descriptive—they are essentially part of the article text—not bibliographic. Factual claims in captions may be footnoted, but readers looking for true citations will be expected to click through to the image's page and read the metadata below it. While not explicitly prohibiting citations of images, the Manual of Style for captions states "Unless relevant to the subject, do not credit the image author or copyright holder in the article." Wikipedia:Citing sources notes that "For an image or other media file, details of its origin and copyright status should appear on its file page."

There are good reasons for this state of affairs. Many images used in Wikipedia articles are drawn or photographed by Wikipedia contributors, and it is standard practice for Wikipedia authors not to be credited in the article itself. Clicking through to the image description page is similar to having to click on the history tab to see the authors. Additionally, allowing image credits would raise the possibility of users contributing for self-promotional reasons, or even fighting over an image's inclusion where they have a personal stake in the credit.

Historical images
However, there is a certain class of images where there is no danger of self-promotion and where citations would be especially relevant in the article itself: historical images from cultural institutions. Such images share several important characteristics. They are usually more than merely decorative; being historical, they are primary source documents relating informational content about the article subject. As well, as documents, they typically have a historical title, creator, and publisher which is not merely important for attribution purposes, but also helps contextualize the work. For these reasons, bibliographic citations of historical imagery provide the same sort of useful guidance to researchers as references of textual material. It is important to note that citing images is standard practice in academic writing.

Such documents also typically come from a repository with authoritative metadata about the works. And the citing of that information in articles for images, when it would be cited if in the form of text, would improve the reliability of the documents and the article. For example, is this image of the purported David Wills letter inviting Lincoln to give an address at Gettysburg, as displayed in the article, simply uploaded by a descendant on their own authority, or is it a national treasure cataloged and held by the Library of Congress? It is the latter, and a citation would not only make that clear, but direct readers to a repository with further research materials.

That is, citing historical imagery in articles, rather than being a mere image credit, is intended to enhance the article in the same way that citing sources for any other type of information does (emphasis added):

"By citing sources for Wikipedia content, you [1] enable users to verify that the information given is supported by reliable sources, thus improving the credibility of Wikipedia while showing that the content is not original research. You also [2] help users find additional information on the subject;"

How does it work?
Please see the sample page for a full mock-up of this proposal.

Adding a footnote to an article for a primary-source document presents at least three challenges: how to position and format the footnote within the article, how to position the list of references with image citations, and what bibliographic style to use for the citations. For this proposal, we have chosen to place footnotes in the caption area, but directly before any caption text, so that the image footnote is not confused for a footnote of the caption text itself. To clarify that the footnotes refer to the image, I have numbered them separately with "[image 1]" footnotes. This means that they will be listed separately in the references section, and so we have created a separate "Images" subsection in the references section. It is important that the citation style includes the possibility of metadata important for historical and visual material, like the medium, repository, and unique identifier from the repository. For the mockup, we did this with a custom citation template, which could likely be merged with a suitable existing template to display the same information (I'm not incredibly familiar with them, so this was easier for me), or at least renamed before being used in articles.

In technical terms, the footnotes are rather simple to create. Simply use the citation template and  Inez Milholland at the March 3, 1913, Suffrage Parade]]
 * }
 * }
 * }

Proposed changes
This proposal is that WP:CAPTION and WP:CITE be modified with a sentence like the following added:
 * Optionally, a primary-source historical image (such as a famous painting or historical document) with descriptive metadata from a reputable cultural institution may be cited inline.