An image tag is a label applied to a container image in a repository that distinguishes a specific image from other images in an imagestream. Typically, the tag represents a version number of some sort. For example, here v3.11.59-2 is the tag:
registry.access.redhat.com/openshift3/jenkins-2-rhel7:v3.11.59-2
You can add additional tags to an image. For example, an image might be assigned the tags :v3.11.59-2 and :latest.
{product-title} provides the oc tag command, which is similar to the docker
tag command, but operates on imagestreams instead of directly on images.