The images, shared on Friday, show the 71-year-old Chicago-born pontiff wearing a green robe and standing behind a makeshift altar on the tenth floor of Rome's Gemelli Hospital. The Vatican press office said the Pope "celebrated with the medical and nursing staff" and thanked workers for their service.
The Vatican had described Tuesday's operation as "successful" and said it proceeded without complications, before revealing that the Pope had been diagnosed with lung cancer. Surgeons removed the whole lower lobe of the Pope's right lung "to ensure the procedure was radical," the Vatican said.
"After the operation, the Pope awoke normally and returned after a brief period of observation to his room," the Vatican said earlier, adding that he spent a "peaceful night" at the hospital.
On Friday, the Pope's doctors said tests had shown "a steady improvement in his general condition" since the procedure and that a chest X-ray indicated "good recovery of the operated lung."
The diagnosis has left Catholics questioning what comes next, according to a related BBC report.