Reviewed as of 1 October 2026. If you spot an error, write to me.
Many museums, archives and libraries offer images for download. That does not mean they can all be used for any purpose. Each file carries a rights statement, and it is that statement, not the name of the portal, that tells you what you can do. The guide on images of public domain works explains what is free by law. This one explains how to read what each record says and how to credit it.
Look at the record, not the portal
An ‘open’ portal may bring together images with very different licences. Before using one, open its individual record and look for the rights statement. A museum’s general legal notice does not replace the specific licence of a file, and the licence of the data describing a work is not that of its image: a repository may release the metadata but not the photograph.
The most common statements
- CC0. The rights holder waives their rights to the extent the law allows. It is the most open option there is.
- Public Domain Mark. It is not a licence: it is a label showing that the institution considers the work free of known copyright.
- CC BY. Allows copying, distribution and adaptation, including for commercial purposes, provided you credit the author, link to the licence and indicate whether you have made changes.
- CC BY-SA. The same, but anything you create from the image must be shared under the same licence.
- CC BY-NC. Excludes uses whose main purpose is commercial. ‘Non-profit’ does not necessarily mean ‘non-commercial’.
- CC BY-ND. Allows the image to be shared as it is, but not modified versions to be distributed.
- Standardised statements such as ‘In Copyright’, ‘No Known Copyright’ or ‘Copyright Not Evaluated’. They show the status known to the institution, not a permission.
- The repository’s own terms. These have to be read one by one.
What no licence settles
The licence of a photograph does not always cover what appears in it, as the guide An image licence does not always cover the work depicted explains. Nor does it settle the image rights of the people portrayed or the use of trade marks. And in Spain, even when a work is in the public domain, you must still acknowledge its author and respect its integrity.
How to credit
Acknowledging authorship is both an obligation and a courtesy, but it is no substitute for permission. In 2023 the Spanish Supreme Court ruled against a publisher for reproducing a translation in full in a book, even though it had credited the translator.
A good credit includes, depending on the case:
- Author of the work, title and date.
- Institution that holds it.
- Photographer, if known.
- Licence, with its version and a link, for example ‘CC BY 4.0’.
- Any changes you have made, such as cropping or a colour change.
Keep the evidence
When you download, save the address of the record, the date, the file identifier and a screenshot of the rights statement. A repository’s licences can change, and keeping proof of what it said on the day you downloaded is up to you. The master artwork record template has fields for noting this down.
Common mistakes
- Writing ‘Source: internet’.
- Crediting the museum and forgetting the author or the photographer.
- Writing ‘Creative Commons’ without saying which licence.
- Copying the credit from an intermediary website instead of the original record.
- Not keeping proof of the licence.
Further reading
On the open conversation
This guide is for guidance only. If you work in a repository or in rights management for a collection and can clarify any point, this notebook remains open.