Miscellaneous topics that do not fit into specific categories.
You cannot copyright artwork created by a machine. It doesn't matter how many times you change your prompt. If you want to add a watermark, add, 'Created by Bing Image Creator powered by Dall-E'.
No one owns the images, and they might be created by Bing for someone else, so you cannot stop someone else from using the same image. This has been tested in court here: https://www.wired.com/story/ai-art-copyright-matthew-allen/
However, by using AI generated images, you may be breaching someone else's copyright because the machines are trained using other people's artwork and there are currently lawsuits going through the courts over artwork being replicated by AI machines without the permission of the copyright owners. This is why Microsoft doesn't claim copyright ownership either. You're on your own defending your use of it. At your own risk.
One lawsuit is here, but there are many: https://arstechnica.com/information-technology/2023/01/artists-file-class-action-lawsuit-against-ai-image-generator-companies/