You gave a very interesting link!!
Every painting there donesn't tell an history only.
They tell more than that.
Some paintings there I've already known, some are new to me.
1. My opinion about the last two paintings in that page:
Erich Von Deniken is talking a lot about tem in his books.
Those beings are actually aliens from Orion Belt (The "Greys"), which God (if you wish to call him that way) created before the human beings (and the Pleidians also, who come from the Pleidas..)
The creation of those 2 star systems is written in the Bible,
I try to find the source again.
Anyway, The Greys and the Pledians are older than us.
They belong to different councils..
While the Pleidians want to help us, the Greys are controlled by other bad aliens, who represent the Draconian Council.
Anyway, maybe the Greys tried to build alien colonies, research and genetic labs also in Australia. I assume they were expelled by the Formal Alien Council(
http://adriandvir.tripod.com/alienscauncil.html).
But even this days, the Greys, under the control of the Reptilians, are trying to get to Earth for their evil deeds.
Groove on. Do not worry.