(CNN) After Barbara Bush's funeral, everyone was talking about the photo.

No, not that photo -- of the four ex-presidents, three former first ladies and current first lady Melania Trump -- that made the rounds on social media over the weekend.

The other much-talked about picture was a photo of the socks worn at the funeral by former President George H.W. Bush, who is known for wearing bold, patterned socks.

The photo is a close-up of Bush's ankles, adorned with black socks decorated with a stack of blue, red and yellow books. It's a nod to Barbara Bush's main cause during her White House years: literacy.

Motivated by her son Neil's dyslexia, she chose family literacy as her main cause while first lady.

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