A Timeless Photo

What makes a timeless photo?  I don't know and it's been on my mind.

"Nastassja Kinski and the Serpent" (1981)

(c) Richard Avedon

Fashion obviously can date a photo, but not I'd argue in the same way as old cars might.

Let me pick an example of a photo that I've never liked and feel dates more with every passing year.  "Nastassja Kinski and the Serpent" taken by Richard Avedon in 1981, originally for Vogue and then made into a high-selling poster.  In 2008 a print of it sold at auction  for $74,500.  I've always thought it was tacky though I can't pinpoint why I feel that.  Is it my perception that it's dating badly, or is it still as popular as ever?  It's hard to tell really.  Yes you could look at monetary value and check auction prices over the thirty plus years of its existence but do I want to start judging art on that level?

(c) Henri Cartier Bresson.

Perhaps I should pick a photo that I believe has absolutely held the test of time.  My go to would probably be something by Henri Cartier-Bresson.  It goes without saying I'm sure that I could have picked any number of his images. Why do I think this image will look as good today as in a hundred years from now?  

1. The composition is great.

2. There are no hints of modernity.

3. Being monochrome it doesn't contain any colour-processing artefacts to bring it back to a particular time period.  E.g. The gorgeous Kodachrome.

Is that is?  Did I miss anything obvious?