The photographs of Kim, wearing sunglasses and looking generally healthy as he talked outdoors with women soldiers, were the first in nearly two months.
But the surrounding greenery suggested the pictures may be from before his last public appearance in the middle of summer and not from recent weeks, when trees in the northern part of the Korean peninsula would have begun changing color, local media quoted government sources and experts as saying.
"There is little chance they were taken in October," the JoongAng Ilbo daily quoted Lee Eun-joo, a horticulture specialist at Seoul National University, as saying.
Yonhap news agency quoted an unidentified intelligence source as saying: "Having analyzed the look of Kim Jong-il in the picture, it is impossible to know what year the pictures were taken but looking from the environment, it's likely it was July or August."
TIGHTLY GUARDED SECRET
"As long as
Another government official said the pictures "fall short of being a decisive basis to confirm" that Kim was currently in good health, but added it was difficult on the other hand to say conclusively that they were not taken in recent days.
Kim's health and his whereabouts are the among the North's most tightly guarded secrets. State media typically does not indicate the timing of his public appearances.
Medical professionals who were shown Kim's pictures said there was little to indicate he was suffering from lingering symptoms of a stroke, South Korean media said.
Kim failed to appear at a celebration marking an anniversary of the ruling Workers' Party of Korea on Friday after the North's official media said about a week earlier he had attended a soccer match, the first mention of a public appearance in about 50 days.
In September, Kim did not show up at a military parade on the 60th anniversary of the founding of the communist state, raising questions about the leadership of
South Korean intelligence sources said they believed Kim was recovering and that he had not lost grip on power.