BEIJING — The word on the street these days, whether in Washington or Beijing, is that the United States is on the decline and China is on the ascent. But it has taken nothing more than a cup of coffee and a backpack to show that American officials can still evoke awe, respect and envy among Chinese, even if unwittingly.

A photograph taken last Friday of Gary F. Locke, the new United States ambassador to China, buying coffee with his 6-year-old daughter and carrying a black backpack at a Starbucks in the Seattle airport has gone viral on the Chinese Internet. The seemingly banal scene has bewildered and disarmed Chinese because they are used to seeing their own officials indulge in privileged lives often propped up by graft and bribery and lavish expense accounts.

It was an unintended charm offensive, but this humble image of American officialdom has no doubt helped pave the way for Vice President Joseph R. Biden Jr., who landed in China on Wednesday night for three days of meetings with Chinese leaders.

Mr. Locke and his family were waiting to fly to Beijing when a Chinese-American businessman shot the photograph and posted it on Sina Weibo, a popular Chinese social networking site. It has been reposted over 40,000 times and has generated thousands of comments. State news organizations have weighed in with favorable articles about Mr. Locke, a former governor of Washington State and President Obama’s first Commerce secretary, who on Tuesday presented his credentials to President Hu Jintao of China to start his posting.