Verified in OCP 3.6:

openshift v3.6.86
kubernetes v1.6.1+5115d708d7
etcd 3.1.0


#  oc create -f - << EOF
> {
>     "kind": "ImageStream",
>     "apiVersion": "v1",
>     "metadata": {
>         "name": "rhel7-test"
>     },
>     "spec": {
>         "dockerImageRepository": "registry.access.redhat.com/rhel7"
>     }
> }
> EOF
imagestream "rhel7-test" created

[root@host-8-172-122 master]# oc get is
NAME         DOCKER REPO                        TAGS                            UPDATED
rhel7-test   registry.access.redhat.com/rhel7   latest,7.3,7.3-89 + 2 more...   1 second ago

# oc get imagestreamtag rhel7-test:latest -o json
{
    "apiVersion": "v1",
    "generation": 2,
    "image": {
        "dockerImageLayers": [
            {
                "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-gtar",
                "name": "sha256:4e5a7647df476dcb309aa02f6901239300e7103a914fd92acf540372c1dafe0c",
                "size": 72175335
            },
            {
                "mediaType": "application/vnd.docker.container.image.rootfs.diff+x-gtar",
                "name": "sha256:0001a3087112018853b83f67ffc311dab755d14393a69852d5e2f4aa01b35361",
                "size": 1194
            }
        ],

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHSA-2017:3389