Commons:Enforcing license terms

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COM:ENFORCE

Where external reusers of Commons content do not respect the specified license terms, only the copyright holder can enforce the license terms. Neither the Wikimedia Foundation nor the Commons community is in a position to seek out license violations by reusers, or to enforce license terms when violations are pointed out.

This page describes some tools for copyright holders to identify their work when they upload it on Commons (so that reuses outside Commons can be detected), and provides some guidance on dealing with reusers who violate license terms.

Note: This page is about uses of files outside Commons. Files which are copyright violations on Commons can be removed by requesting deletion. The most straightforward cases can be handled by placing {{copyvio|source=URL}} on the file page, replacing URL with the non-Commons webpage the file was taken from. If necessary, use the Commons:Help Desk.

Clarity of license terms[edit]

Most aspects of a license are clear enough from applying the relevant license template. The exception is attribution: this is not always made clear enough by uploaders. If you want reusers to credit you correctly, be sure to make the required attribution as clear as possible. One way to do this is to use the {{Credit line}} template in the |attribution field of the {{Information}} template. Alternatively, many license templates, like {{Self}} or {{Cc-by-sa-3.0}}, have |attribution parameters to specify the desired form of attribution. (If you use both, be sure not to contradict yourself!) Examples of different types of attribution can be found at Commons:Credit line.

Tools for identifying your work[edit]

Watermarks
- Visible watermarks Do not add visible watermarks to your images, such as printing your name in the corner. These will be removed as they affect image quality.
- Invisible watermarks (aka digital watermarking). Invisible watermarks identify the author and license without visibly damaging image quality and are designed to be difficult to remove. The most popular provider is Digimarc, but more affordable competitors like SignMyImage^{[dead link]} exist. Most digital watermarking services offer a subscription to a search engine that tracks uses of your images throughout the web.
EXIF Add EXIF metadata to your image describing the author and license. Many cameras and image processing software can be configured to do this automatically, and it will remain with the image when it is downloaded and copied. Although EXIF data is easily removed by third parties, most do not do so, allowing you to prove that the image belongs to you and demand compliance.
File description page - the file description page gives you scope to clarify attribution and sourcing. You can, for example, if you have a Flickr account or other website where you have uploaded the image, add that as a source in the "Source" field of the {{Information}} template.
Image searches Google's Search by Image provides a free option for finding uses of your image throughout the web. However, unlike digital watermarking it does not prove that the images belong to you and may sometimes produce unpredictable or incomplete results.