Examples described relate to container images. An example method may include generating a mapping of respective unique identifiers of container images of a software container and respective metadata of the container images, validating the mapping against a rule to identify a unique identifier of a mapped container image that meets the rule, generating a target mapping that includes the unique identifier of the mapped container image that meets the rule and the action specified in the rule, and performing the action specified in the rule on the mapped container image corresponding to the unique identifier in the target mapping.