Education Minister Heng Swee Keat responded last night to comments online about a photograph of former prime minister Lee Kuan Yew's 91st birthday celebration which seemed to have been altered.

The photograph was uploaded on Mr Heng's Facebook page on Tuesday.

Responding to The Straits Times, a spokesman for Mr Heng acknowledged that some adjustments were made to the photo: "This was a personal photograph taken with a simple camera. The photograph had some glare in the background. An amateur adjustment was made to remove the glare."

The image showed Mr Lee with current and former staff. They included Mr Heng, who served as his principal private secretary from 1997 to 2000, and Singapore Press Holdings chief executive Alan Chan, who held that position before him.

As of 11pm yesterday, the post had drawn nearly 3,000 likes and more than 300 shares.

After the photograph was uploaded on Mr Heng's Facebook page, some netizens asked if the image was doctored, citing its "unusually black" background. Others said it looked like a Photoshop job gone wrong and asked for an explanation.

User Shi Kexin said: "Making enhancements like adding light and saturation is ok. But changing entire background to give impression you are in another place shouldn't be encouraged. Or else we won't know what is real and what is fake anymore."

WALTER SIM