C.5.

<configuration>
  <generator>
    <config>
      <spring-boot>
        <fromMode>{istag|docker}</fromMode>
        <from>{image locations}</from>
      </spring-boot>
    </config>
  </generator>
</configuration>

<configuration>
  <generator>
    <config>
      <karaf>
        <fromMode>{istag|docker}</fromMode>
        <from>{image locations}</from>
      </karaf>
    </config>
  </generator>
</configuration>

//build from Docker-formatted image directly, registry location, image name or tag are subject to change if desirable
-Dfabric8.generator.fromMode=docker
-Dfabric8.generator.from=<custom-registry-location-url>/<image-namespace>/<image-name>:<tag>

//to use ImageStream from different namespace
-Dfabric8.generator.fromMode=istag //istag is default
-Dfabric8.generator.from=<namespace>/<image-stream-name>:<tag>