Watermark AI-generated image files

[julien-nc]

@nextcloud/integration

We could watermark all the images generated by the task processing providers. If we do it at the task processing level, it saves us the effort of implementing it in all providers.

• Visible watermark: We could insert a little image (logo + text) in a corner of images. Something like the assistant logo and a label like "AI-generated"
• Invisible watermark
  • We can store information as EXIF data. We could store a comment. We might be able to use the Php imagemagick extension or the GD one. It would better than using lsolesen/pel which is abandonned.
  • There might be a way to embed something invisible in the image itself. For example: https://github.com/SebaOfficial/Steganography

This could be done right before storing the images in appdata, when the task results are set by the provider.

For context: the watermarking is a requirement for the AI act, even if it can easily be erased we have to implement it to the best of our abilities. If there is an easy method to make an invisible watermark, we have to do it, and if it is not realistic a simpler method like EXIF / ID3 is likely sufficient.

[marcelklehr]

At the moment it is not clear from the docs or the namíng that the TaskProcessing API should only be used to produce AI-generated files. I would suggest to decide whether we want to restrict the APIs usage to AI only, if it turns out that we want that, we can add the watermarking to the server, otherwise, I think it would be better to have it in the individual apps.

[oleksandr-nc]

How about implementing this as an additional flag? If the watermark=True flag is set, then TaskProcessing will add a watermark. If watermark=False, then it won't.
Apps should decide for themselves whether to set the flag or not (they will only want to set it at the final stage, and in a chain-of-tasks it will be False at all preceding stages).

[EntityinArray]

IMO, "invisible" watermarking is a bad idea, it can easily be erased and will just malform data in unexpected ways
How would people even verify these watermarks if they are invisible?

Adding a friendly comment into EXIF or ID3 is fine
And even then, i think its out of scope for NC, processing tools should leave these comments themselves.

[DaphneMuller]

Just to be clear, it is not out of scope for Nextcloud, the watermarking is a requirement for the AI act, even if it can easily be erased we have to implement it to the best of our abilities. If there is an easy method to make an invisible watermark, we have to do it as per law and in that case EXIF / ID3 is not sufficient.

In what way would it malform data in unexpected ways? Do you have a concrete example?

[julien-nc]

We could use steganography. There are Php libraries for that like https://github.com/SebaOfficial/Steganography . It does not seem too hard to implement that with any library: https://thedebuggers.com/image-steganography-hiding-text-using-php/

[EntityinArray]

In what way would it malform data in unexpected ways? Do you have a concrete example?

Say the AI tools itself adds a watermark, then nextcloud adds its watermark, then tool that requested the image from nextcloud adds a watermark and it turns into a mess

I think watermarking should only be handled at the source (in the AI image generating tool itself)
Nextcloud doesn't generate any AI content by itself, so I think you guys are safe from this law (i'm not a lawyer though)