Commons:Credit line

This page is an essay; it contains the advice and/or opinions of one or more Commons contributors.
It is not a Commons policy or guideline, and editors are not obliged to follow it. Please update the page as needed, or discuss it on the talk page.

The credit line or attribution line holds information that the author of the work requests all users to include with the work, as a condition of use enforced by the license. Specifically widely used Creative Commons CC-BY licenses and GFDL licenses require all users of the work to attribute the author.

Although the term "credit line" is used here, the required attribution need not be specified as a credit line, neither is the format of the attribution specified.

Some works might have specific instructions from the author on how they would like their work to be attributed. Those requests must be honored, as long as they fall within what is required by the license, and should be honored, if reasonable, otherwise. If the author did not give explicit instructions, you must still attribute to the author and the minimal and suggested forms of attribution can be found below.

Credit lines required by license

Creative Commons

CC-BY and CC-BY-SA licenses

According to Creative Commons CC BY and CC BY-SA licenses, reusers must attribute the work by providing a credit line. Section 4b (Section 4c in CC BY-SA 3.0) of full license provides the details. Included below are the most relevant fragments:

If You Distribute [] the Work or any Adaptations or Collections, You must, unless a request has been made [not to], keep intact all copyright notices for the Work and provide, reasonable to the medium or means You are utilizing:

(i) the name of the Original Author (or pseudonym, if applicable) if supplied, and/or if the Original Author and/or Licensor designate another party or parties (e.g., a sponsor institute, publishing entity, journal) for attribution ("Attribution Parties") in Licensor's copyright notice, terms of service or by other reasonable means, the name of such party or parties;
(ii) the title of the Work if supplied;
(iii) to the extent reasonably practicable, the URI, if any, that Licensor specifies to be associated with the Work, unless such URI does not refer to the copyright notice or licensing information for the Work;

In other words, unless author or licensor asks not to be credited, reusers distributing files found at Wikimedia Commons must provide credit line with license and author. Also author might request for credit line to include: other "Attribution Parties" (like Wikimedia Commons), URI (like web pages), or title. Reusers can choose format of the credit line "reasonable to the medium or means" as long as all required components are present. Example Credit lines in minimal format:

License	Author	Source	Credit line	Notes
{{cc-by-sa-3.0}}	John Doe	Own work	John Doe / CC-BY-SA-3.0	Minimum information required by the license for files without explicit Credit line field specified by the author
{{self\|cc-by-sa-3.0\|GFDL}}	John Doe	Own work	© John Doe / Wikimedia Commons / CC-BY-SA-3.0 / GFDL	Example credit line for dual license file with Wikimedia Commons as extra "Attribution Party"
{{cc-by-sa-3.0}}	User:Example	Own work	© User:Example / Wikimedia Commons / CC-BY-SA-3.0	Example credit line for users who do not provide their real names.
{{cc-by-sa-3.0}}	John Doe	Own work	© John Doe / http://example.com / CC-BY-SA-3.0	Example credit line with external website specified by the author.
{{cc-by-2.5}}	John Doe	Own work	Marble Lady by John Doe / CC-BY-2.5	Example credit line with title specified by the author.

CC-SA licenses

License	Author	Source	Credit line	Notes
{{cc-sa-1.0}}	John Doe	Own work	CC-SA-1.0	Minimum information required by the license

Note that attribution in accordance with best practices may be demanded by law in many European countries (cf "moral rights"), regardless of any general waivers such as CC-SA.

CC-PD licenses

CC Licenses not requiring attributions: {{Cc-zero}}. Please consider using an optional courtesy credit line.

Note that attribution in accordance with best practices may be demanded by law in many European countries (cf "moral rights"), regardless of any general waivers such as CC-zero.

Free Art License

The Free Art Licence considers it vital to announce the image is free and under a copyleft licence, which is linked to (or the URL spelled out in print). This is in addition to information on the author, the title of the work, the date of the work, any other authors contributing to the work and the location of the original work(s). The following format is required:

[Name of the author, title, date of the work. When applicable, names of authors of the common work and, if possible, where to find the originals].

Copyleft: This is a free work, you can copy, distribute, and modify it under the terms of the Free Art License

For example:

Copyleft: This is a free work, you can copy, distribute, and modify it under the terms of the Free Art License

GNU Licenses

License	Author	Source	Credit line	Notes
{{self\|cc-by-sa-3.0\|GFDL}} {{GFDL\|migration=relicense}}	John Doe	Own work	© John Doe / Wikimedia Commons / CC-BY-SA-3.0 / GFDL
{{GFDL}} only (now called {{GFDL\|migration=opt-out}}) {{GFDL-1.2}}	John Doe	Own work	Copyright (c) John Doe. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.3 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".	You also have to include full text of the license.

Courtesy credit lines

Public Domain media do not require a credit line or any kind of attribution; however, reusers are encouraged to attribute the author (if known) and inform users that the work was released into the public domain. (Public domain works are not under copyright, and thus should typically avoid the use of the © symbol.) Below are suggested formats for the reusers:

License	Author	Source	Credit line
{{PD-self}} {{PD-author}} {{PD-heirs}}	John Doe	Own work	John Doe / Wikimedia Commons / Public Domain
{{PD-old}}	John Doe	publication / self-scanned	John Doe / Public Domain
{{PD-self}}	[[user:JohnDoe]]	Own work	user:JohnDoe / Wikimedia Commons / Public Domain
{{anonymous-EU}} {{PD-anon-1923}} {{Anonymous work}}	anonymous	publication	Public Domain
{{PD-textlogo}} {{Trademark}}	Acme Corp	publication	™ Acme Corp

Automatic handling of attribution by reusers

API:Imageinfo does offer image license info with iiprop=extmetadata - see for example https://commons.wikimedia.org/w/api.php?action=query&titles=File:Gull%20portrait%20ca%20usa.jpg&prop=imageinfo&iiprop=metadata%7Ccommonmetadata%7Cextmetadata with useful data in Credit and AttributionRequired entries.