ImageFromString parses a docker image string into three parts: repo, tag and digest.

ImageTagIsValid ensures that a given image tag is compliant with the OCI spec.

ModifyImageRepository takes an imageName (e.g., repository/image:tag), and returns an image name with updated repository.

ModifyImageTag takes an imageName (e.g., repository/image:tag), and returns an image name with updated tag.

SemverToOCIImageTag is a helper function that replaces all non-allowed symbols in tag strings with underscores.

Image type represents the container image details.