The configuration imagestream.spec.tags.importPolicy.scheduled
determines whether the imagestream is configured to periodically check
for updates. This is useful when working with an external container
image registry, to periodically re-import an image, for example to
get latest security updates.
You can set the scheduled update by calling:
$ oc patch imagestream NAME -n NAMESPACE --type merge -p '{"spec":{"tags":[{"name":"TAG_NAME","importPolicy":{"scheduled":true}}]}}'
For more information, follow the
ImageStreams documentation