The Berne Convention (an international agreement) requires at least 50 years of protection, and the US signed it. But 50 is a lot less than 95.

I always wondered what strings hold the Berne Convention (and similar treaties) together. It seems like they got adopted by incredibly broad swathes of countries-- ones with wildly different social and economic needs and norms. Why would countries that can't even agree on any other nuts-and-bolts matter suddenly all line up to defend Mickey Mouse?

My first guess was promises of reciprocality, but that seems like a hard sell to countries without a meaningful IP economy.

I can't imagine it being enforced with bullets. There's no way to rally troops to defend a copyright that doesn't make you look like the bad guy.

Was it smuggled in as part of other trade agreements? (If you want to sell us $resource_you_actually_have, you have to also agree to worship the almighty circled C?)

It was initially signed as a standalone agreement 150 years ago for the sake of reciprocity - rightsholders in different European countries were unhappy with pirate publishers over the border selling their works without payment.

Today though pretty much everything in the Berne Convention is part of agreements you have to implement to join the World Trade Organisation, which is a pretty big motivation to abide by it.

Copyright enthusiasts have done their best to have the 50 or 70 year term written into as many trade agreements as possible, e.g., WTO.

However, the US probably has enough weight that other countries would just have to adapt if it wanted a shorter term, but at present there's no evidence of much political efforts for one.

50 years of protection after the death of the author.

It's 70 in the US now. From the US Copyright Office: "As a general rule, for works created after January 1, 1978, copyright protection lasts for the life of the author plus an additional 70 years. For an anonymous work, a pseudonymous work, or a work made for hire, the copyright endures for a term of 95 years from the year of its first publication or a term of 120 years from the year of its creation, whichever expires first. For works first published prior to 1978, the term will vary depending on several factors."

Yes, I know. The requirement of the Berne convention is 50 years after death. The US goes twenty years beyond that.

The author is the one that records it, not the tool used to create it.

Nothing AI created can have copyright under current law.

In the US, indeed. But in the UK the runner of AI can hold a copyright. Which I think is stupid but that's hardly the first dumb copyright thing.

For something like img2img with Stable Diffusion, if the starting image is copyrighted by someone else I'd expect that the output image is a derivative work of the starting image.

The question is about new copyright in both cases, not subsisting copyright. You hold the copyright to the elements originating with you in a derivative work.