We can''t read the imageConfig from master-config.yaml as this is client command. Maybe we can provide `--image` flag for oc ex diagnostics where you can specify what images you want to pull. Moving this off the 3.9 blocker list.
Actually this is duplicate of https://bugzilla.redhat.com/show_bug.cgi?id=1475680 *** This bug has been marked as a duplicate of bug 1475680 ***