Explanation
Tagging the image with 'nginx:immutable' is not how a user can prevent an image, such as 'nginx:latest', from being overwritten by another user with push access to the repository. Tagging the image with
'nginx:immutable' will only create a new tag for the image, but it will not prevent the original tag from being overwritten. To prevent an image tag from being overwritten in Docker Trusted Registry, the user can use the DTR web UI to make the tag immutable1. This will prevent anyone from pushing a new image with the same tag, even if they have push access to the repository1. Alternatively, the user can also use the DTR API to make the tag immutable2. References: Prevent tags from being overwritten), DTR API reference)