An image contains the code used to create a deployment. Then, a deployment can be created from an image, which should then create a replica set (which is the number of pods that should be created), and then the pods should be created.
If you are not familiar with the oc command, refer to OpenShift - Getting Started with the oc command.
Before importing an image, the oc get images command can be used to determine if the image has already been imported.
~]# oc get images
NAME IMAGE REFERENCE
sha256:0089883f8e4387618946cd24378a447b8cf7e5dfaa146b94acab27fc5e170a14 registry.example.com/jboss-webserver-3/webserver30-tomcat8-openshift@sha256:0089883f8e4387618946cd24378a447b8cf7e5dfaa146b94acab27fc5e170a14
sha256:0155e28b6b10d6fba7144df9ce33105acbab32766836baacc67c76b900a58772 registry.example.com/redhat-sso-7/sso70-openshift@sha256:0155e28b6b10d6fba7144df9ce33105acbab32766836baacc67c76b900a58772
sha256:03416282b034b93614ab2af74441ce481226bcf0b0b6c614cacd1b6f008f9792 registry.example.com/jboss-eap-6/eap64-openshift@sha256:03416282b034b93614ab2af74441ce481226bcf0b0b6c614cacd1b6f008f9792
sha256:03795eb1e54f94ffb822b8b3997b5f5bbeaa20bdf7006841864738d1eb58054b registry.example.com/rhpam-7/rhpam72-businesscentral-openshift@sha256:03795eb1e54f94ffb822b8b3997b5f5bbeaa20bdf7006841864738d1eb58054b
The oc import-image command can be used to import an image from an external registry, such as registry.redhat.io, registry.access.redhat.com, registry.ci.openshift.org, and the list goes on. In this example, an image named openjdk18 is imported.
~]$ oc import-image openjdk18 --from=registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift --confirm
imagestream.image.openshift.io/openjdk18 imported
If the image is stored in a secured external registry, you may need to use the podman login command to log into the external registry.
sudo podman login registry.redhat.io
And then use the podman pull command to pull the image from the external registry.
sudo podman pull registry.redhat.io/openshift4/ose-hello-openshift-rhel8:v4.7.0-202205312157.p0.g7706ed4.assembly.stream
Now the oc get images command should include the imported image.
~]$ oc get images
NAME IMAGE REFERENCE
sha256:6f75262945716ac8f9bdcf1c26ba2eb962764f0e89ba1745933be553a6b58aa4 registry.access.redhat.com/redhat-openjdk-18/openjdk18-openshift@sha256:6f75262945716ac8f9bdcf1c26ba2eb962764f0e89ba1745933be553a6b58aa4
And the oc get imagestreams command should also include the imported image.
~]$ oc get imagestream openjdk18
NAME IMAGE REPOSITORY TAGS UPDATED
openjdk18 image-registry.openshift-image-registry.svc:5000/foo/openjdk18 latest 15 hours ago
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