As part of a survey (collecting environmental data from the public) my participants can choose to provide their name or to contribute anonymously. Part of the survey includes submission of photos that we wish to be able to reuse under the terms of a CC-BY license.

To comply with that license we need to acknowledge the source of the photos wherever they are re-used - which is fine for named contributors, but potentially problematic for users who wish to remain anonymous.

This must be a problem that many others have encountered, what is the simplest solution that respects the licence but avoids too much special-case legalise?

Can an anonymous CC-BY work be legitimately 'acknowledged' using something like "anonymous my_survey participant"?

If not, is there a simple way to allow CC0 to be applied to anonymous photos while using CC-BY for the rest? Excessive legalise will scare away many of my users.

  • 2
    Not enough time to make a full answer, but CC BY 4.0 says of attribution that you must "retain the following if it is supplied by the Licensor with the Licensed Material..." So if the licensor taking your survey explicitly opted not to supply authorship info, then the license excuses you from retaining any such non-existent info.
    – apsillers
    Jun 4, 2019 at 3:25

1 Answer 1


The CC licenses – and copyright1 in general – allow the creator/artist/author to opt out of attribution. The creator can decide under which name or pseudonym they should be attributed, or whether they would prefer not to be associated with the work at all. For you, this might be a simple checkbox:

If you upload a photo, you agree to license it under the CC-BY 4.0 license. This allows anyone to use the photo for any purpose, as long as they attribute you. How would you like to be attributed?
[x] attribute photo to __________ (your name)
[_] stay anonymous

Your suggestion of attributing to “anonymous my_survey participant” is fine. In digital media, the attribution can also link to a page that is about the licensed work. For example, you could link to a page about your survey. Technically, the CC licensor (the author) can decide this, but I don't think there could reasonably be any different link target in the context of your survey.

Allof this is fine for the creator, but what about you? How do you know that you received a valid CC license? What if the survey contributor does not hold the necessary rights to the photo? You may very well want to keep contact information for the contributors on file, even if you don't show this info publicly. This isn't directly about the licensing, more about CYA. Some jurisdictions require you to be able to trace the licensing chain from the author to you. Others might have safe harbour laws that shield you from liability for user-contributed content.

1. That attribution or moral rights are part of copyright is a comparatively European, authors-rights oriented view. It is not generally part of US-style copyright.

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