WeChat and Sina Weibo, two of China's most popular social media, have been awash with nostalgia in recent days, as millions of netizens have posted pictures of themselves at age 18.

The trend was inspired by the fact the arrival of 2018 means even the youngest members of the '90s generation－those born from 1990 to 1999－have now turned 18 and entered adulthood.

While some have simply posted images online of their younger selves, many have also shared memories of their hopes and dreams from that time, as well as reflections on the swift passing of time.

Fang Shilin, an engineer with China Aerospace Science and Technology Corp, posted two pictures on his WeChat Moments feed on Sunday after noticing that many of his friends had uploaded photos.

"I felt it was interesting, so I put up my pictures, too," said the 26-year-old, who in one image can be seen with four friends, all smiling into the camera, as they sit beside West Lake in Hangzhou, Zhejiang province.

"It was a great time. When I look at these pictures, I miss my friends and the old days. Back then, all I wished for was that there would be no more exams in my life. Now the dream has come true," he said with a laugh.

Kou Ying, 53, was not a fan of the trend at first, but she quickly changed her attitude after seeing her friends' old photos.

"When I was 18, I never imagined that I'd be able to study in Germany and become a professional translator. It's interesting to look back," she said. "I haven't changed so much. Even my husband said I am still as simple as I was at 18 years old."

Kou was 18 when she first fell in love. She remembers being "muddled but happy".

"If I were 18 again, I would encourage my friends－especially the women－to read more books. I would aim higher and be more ambitious," she added. "I would spend more time in love before getting married, and I'd see more places overseas."

On Sina Weibo, "photos taken at 18" was one of the hottest search topics on Sunday. Many netizens also urged celebrities to post their photos.

Members of the '90s generation were born at a time when China was beginning to see significant results from its reform and opening-up policy, which was launched in 1978. They grew up with rapid development in the information era.

A lot of attention is also paid to this generation because its members, most of whom have no siblings, grew up in a better family environment than earlier generations. However, many have argued that this has led to the generation being "spoiled".