People looking like nothing you've ever seen, stepping off a vessel unlike anything you've seen, carrying with them disease and weapons that spit fire.
As natives already had people who wore face paint.. the clothes which are mostly absent from the photo would have likely been more startling than the face.
Not sure about that time period, but white meant peace when it came to face paint as well, so this would could across as non-threatening possibly. Surely wearing a symbol of peace and shooting someone could send mixed messages though.