code: private void doUpgradeImage(NamespaceInfo nsInfo) throws IOException {
      Preconditions.checkState(nsInfo.getNamespaceID() != 0,
          "can't upgrade with uninitialized namespace info: %s",
          nsInfo.toColonSeparatedString());
      LOG.info("Upgrading image " + this.getJournalId()
          + " with namespace info: (" + nsInfo.toColonSeparatedString() + ")");
  
      // clear the digest for the most recent image, it might change during
      // upgrade
      checkpointImageDigests.remove(mostRecentCheckpointTxid);
  
      imageStorage.doUpgrade(nsInfo);
    }
docs: Upgrade the local image storage with the given namespace.