Another British fight luminary described it as "the worst decision I've ever seen in boxing".
O'Connor, from Birmingham, was one of two judges who scored the 2017 WBO contest in Manchester between Parker and Hughie Fury at 118 – 110 in the Kiwi's favour.
Fury's promoter Mick Hennessy claimed it represented "corruption at its highest level in boxing - I thought it was an absolute masterclass. Parker wasn't even in the fight."
After the Ritson-Vazquez fight, Hearn shared the photo on Twitter saying: "If that's a phone then BBGBC should immediately remove him."
O'Connor gave Ritson a whopping 117 - 111 advantage, while the other judge who thought Ritson had won scored it more closely.
WBC president Mauricio Sulaiman tweeted: "This image is extremely troubling to any person involved in boxing."
And BBBC general secretary Robert Smith said he was "very, very disappointed", and said he could understand why people thought the Mexican had won.
"I am so frustrated that this seems to have happened. After the hard work we do behind the scenes we have something like this emerging.
"Personally I am so disappointed. I can't say anything more at this point."