After reading the replies, I've reached a conclusion:
I didn't forget anything. 'Dinero' means 'money'. Don't you see money there?
Bans AI-generated images in any contests relate to images for submission is good enough, before forum has new rules against AI-generated images, that I don't believe will be added by forum admins.
If I were you, I would still note that the image was generated with the help of AI, just in case. Given that the forum has never considered uploading images from any source as something against the forum rules, you probably won't have any problems with such images.
It is better to have a note but without it, it will not break any existing rule.
It will be as same as forum rules on plagiarism. If you make plagiarism with your posts, to get money, it will cause tougher punishment. Without financial benefit, punishment on it can be softer.