The Photograph
Here's the full-sized image (© Shriram, CC By-NC-SA 3.0).
That's an Australian eucalypt. They're dramatic trees! A eucalyptus grows a new layer of bark each year, in the process sometimes tearing the existing bark into strips, as the photograph shows. (As someone once said, Australia is a country where the trees shed their barks instead of their leaves.) The trees exude a wonderfully aromatic oil. They also depend on periodic fires.
The redness of the background isn't a Photoshop trick. This is Kata Tjuta, a remarkable rock formation near Australia's iconic Uluru. As the photograph suggests, the formation is made up of iron-oxide-rich conglomerate.
And yes, it's meant to remind you of the Y-combinator.
The Dots
The dot-painting style is frequently found in contemporary Aboriginal art. While it has a certain cliched quality, it is also an instantly recognizable symbol of the culture and ostensibly represents a dreaming (though that is simply a (possibly reductionist) interpretation we place on a concept that does not translate easily—the same way we often approach new programming languages).