Last updated: April 3, 2026

This document describes every licence under which images in the PF Create reference library are made available. It explains what each licence permits, what it requires of you, and links to the official licence text.

All images in the shared library are tagged with their licence. The licence is displayed in the image detail panel and embedded in the file metadata. Where a licence requires attribution, the required credit text is shown in full in the image popup.

CC0 — Creative Commons Zero (Public Domain Dedication)

In plain terms: No rights reserved. Free to use for any purpose, with no conditions.

CC0 is a legal tool that allows creators to waive all copyright and related rights in their work worldwide. Images released under CC0 may be copied, modified, distributed, and used commercially — all without asking permission or giving credit.

What you must do: Nothing.

What you cannot do: CC0 does not waive moral rights, personality rights, privacy rights, or rights other people may have in the work or how it is used. See the Acceptable Use Policy for obligations around images depicting real people.

Official licence text: creativecommons.org/publicdomain/zero/1.0

Public Domain

In plain terms: Copyright has expired or was never held. Free to use for any purpose, with no conditions.

Works in the public domain are not protected by copyright. This typically applies to works whose copyright term has expired, works created by the US federal government, or works where the creator explicitly abandoned copyright before tools like CC0 existed.

What you must do: Nothing, with respect to copyright.

Note: Public domain status can vary by country. A work that is in the public domain in the United States may still be protected in some other jurisdictions. When publishing internationally, consult a qualified lawyer if you have concerns.

PDM — Public Domain Mark

In plain terms: The creator or institution has identified this work as being in the public domain. Same practical effect as Public Domain above.

The Public Domain Mark is a Creative Commons tool used by institutions (museums, libraries, archives) to label works they have determined are free of known copyright restrictions worldwide. It is a declaration, not a licence — the work is in the public domain regardless of the mark, and the mark simply makes that status clear.

What you must do: Nothing.

Official mark description: creativecommons.org/publicdomain/mark/1.0

CC BY 4.0 — Creative Commons Attribution 4.0 International

In plain terms: Free to use, including commercially, but you must give credit.

CC BY 4.0 allows you to share, copy, redistribute, remix, transform, and build upon the material for any purpose, including commercially. The condition is that you must give appropriate credit to the creator or source.

What you must do:

• Credit the creator/institution (name, if provided)
• Include the title of the work (if provided)
• Indicate if you made changes
• Link to the licence: creativecommons.org/licenses/by/4.0

You do not need to do this in any particular format — a caption, metadata field, or credits section is all sufficient, as long as the information is reasonably visible.

Example credit: Photo: Wellcome Collection, CC BY 4.0

Official licence text: creativecommons.org/licenses/by/4.0

CC BY-SA 4.0 — Creative Commons Attribution-ShareAlike 4.0 International

In plain terms: Free to use and adapt, but derivatives must carry the same licence and you must give credit.

CC BY-SA 4.0 adds a “ShareAlike” condition on top of the attribution requirement. If you remix, transform, or build upon the material, you must distribute your contributions under the same CC BY-SA 4.0 licence.

What you must do:

• Credit the creator/institution (same requirements as CC BY 4.0 above)
• If you create a derivative work, release it under CC BY-SA 4.0
• Link to the licence: creativecommons.org/licenses/by-sa/4.0

Important: Using a CC BY-SA image in a larger commercial work without releasing that work under CC BY-SA 4.0 is a licence violation. If you are unsure whether your use constitutes a derivative work, consult a lawyer.

Official licence text: creativecommons.org/licenses/by-sa/4.0

Apache License 2.0

In plain terms: Free to use, modify, and distribute — including commercially — with a few conditions around notices.

The Apache 2.0 licence is primarily an open-source software licence, but is also used for some open-content assets such as emoji and icon sets (notably Noto Emoji). It grants a broad copyright and patent licence.

What you must do:

• Retain any existing copyright, patent, trademark, or attribution notices in the original work
• Include a copy of the Apache 2.0 licence text (or a link to it) when redistributing
• If you distribute a modified version, state that you modified the files

Official licence text: apache.org/licenses/LICENSE-2.0

MIT License

In plain terms: Free to use, copy, modify, merge, publish, distribute, sublicense, or sell — with minimal conditions.

The MIT licence is one of the most permissive open-source licences. Like Apache 2.0, it is primarily a software licence but is used for some open-content assets. It imposes only one condition.

What you must do:

• Include the original copyright notice and the MIT licence text in all copies or substantial portions of the work (or in accompanying documentation).

Official licence text: opensource.org/licenses/MIT

Taiwan Open Government Data License

In plain terms: Free to use, share, and adapt government data from Taiwan — including commercially — with attribution to the source dataset.

The Taiwan Open Government Data License is issued by the National Development Council of Taiwan and applies to datasets released through the Taiwan government’s open data platform. It is similar in intent to CC BY — broad permission with an attribution requirement.

What you must do:

• Credit the source dataset and the originating government agency
• Indicate if you modified the data or derived works from it
• You do not need to release your own work under the same licence

Official licence text: data.gov.tw/license

Quick Reference

This document is a plain-language summary for informational purposes only. It does not constitute legal advice. For the authoritative terms, refer to the official licence texts linked above. If you have questions about a specific use case, consult a qualified intellectual property lawyer.

Questions: [email protected]