"I, for one, am glad to see that he is back, and well!" Trump wrote.
This was Kim's first public appearance in about three weeks after global speculation about his health.
CNN has reached the White House for further information on the president's tweet and about the White House has authenticated the images released by North Korean state media.
On Sunday, South Korean presidential adviser Moon Chung-in told CNN that the North Korean leader was "alive and well" despite speculation about his health.
The adviser to South Korean President Moon Jae-in said Kim had been staying in the Wonsan area, on the country's east coast, since April 13, adding: "No suspicious movements have been detected so far."
This is a groundbreaking story and will be updated.