What will be the use of other people's assets in an open source project?

Question

Law in IT

I write custom styles for one site. The site itself is not mine and I have nothing to do with it, I just improve the appearance. At the same time, I use pictures from another site (formatting them in base64), which is a competitor of the first site. I want to upload all this to github and continue to transfer content from the second site to the first. You need this at least to easily install these styles through a browser extension and to receive updates directly from the repository. The repository is under an open license and the profit from the project is exactly zero. How should I specify the rights to these very assets and can I use them at all? What are the consequences of this and is it possible somehow to avoid letters of kindness through the mention of the author? With a very high probability, no one will even see the repository, but it is interesting to know the solution and the consequences of this.

Answer 1

How should I specify the rights to these very assets and can I use them at all?

Everything is simple here. If the author of these works explicitly allows you to use them in the form in which you use them, you have no problem, if he does not allow you, you cannot. If the author of the works and the terms under which they are licensed are not known or not specified, this is simply intellectual property with which you cannot do anything. In other words, only watch where they are now, but do not copy, distribute or use in personal works.

Repository under an open license

You mentioned that you are using images "from another site" and their license may just be incompatible with yours and prohibit this kind of use and distribution.

What are the consequences of this and is it possible somehow to avoid letters of kindness through the mention of the author?

You can mention the author only on the condition that he agrees to this: either in the form of a clause in the text of the license (that is, there is a clause a la “permitted to use if there is a link to the author”), or in the personal consent of the author that he will have no claims to this form of use.
In case of violation, there will most likely be no consequences for you. The consequences for the individual or organization whose website uses these images can be significant and financial. For example, Lebedev's studio regularly sues companies for using their works without a license. For a rival organization, this is an easy way to drown the opponent in legal costs. Add to this the reputational risks as well - a storm and a scandal may arise.
PS: Not a lawyer.