Rahul Gandhi's emotive post featured Sonia Gandhi and her husband Rajiv Gandhi.
As Sonia Gandhi handed over the leadership of the Congress to a new party president over two decades after she was made its party chief, her "proud" son Rahul Gandhi posted an emotive post on social media in which he recalled his grandmother and former Prime Minister Indira Gandhi had once told him that Mrs Gandhi was the "daughter she never had".
"Ma, Dadi once told me you were the daughter she never had. How right she was. I'm really proud to be your son," said Mr Gandhi, who is leading a Congress foot march from Kanyakumari till Kashmir.
The widely-shared post by Mr Gandhi features Mrs Gandhi with her husband Rajiv Gandhi, a former Prime Minister, who was assassinated by terrorist organisation Liberation Tigers of Tamil Eelam (LTTE) during an election campaign in 1991.
"So proud of you Ma, no matter what the world says or thinks, I know, you did it all for love." Mr Gandhi's sister, Priyanka Gandhi Vadra, said in an emotive Instagram post showing Sonia Gandhi holding a photograph of the late Rajiv Gandhi.
A Gandhi loyalist and a veteran leader from Karnataka, Mallikarjun Kharge took over the charge of the Congress from Mrs Gandhi at a ceremony on Wednesday, making him the first non-Gandhi party chief in 24 years.
"I did my duty to the best of my ability. Today, I will be freed of this responsibility. A weight is off my shoulder. I feel a sense of relief," Sonia Gandhi said at the change of guard event.
Mallikarjun Kharge, 80, won the Congress president election last week, beating his rival Shashi Tharoor by a landslide.
Critics questioned the fairness of the election, suggesting that Mr Kharge, as the "Gandhis -approved candidate", was sure to win.
The Congress has rubbished these allegations, insisting that its election was a big success and was proof of democratic values in the party.