NEW YORK >> What’s in an inch? Apparently, enough missing meat, cheese and tomatoes to cause an uproar.

Subway, the world’s largest fast food chain with 37,000 locations, is facing criticism after an Australian man posted a picture on the company’s Facebook page of one of its famous footlong sandwiches next to a tape measure that seems to show it’s just 11 inches.

More than 100,000 people have “liked” or commented on the photo, which has the caption “Subway pls respond.” Lookalike pictures have popped up elsewhere on Facebook. And The New York Post conducted an investigation that found four out of seven footlong sandwiches were shy of the 12 inches that makes a foot.

By Thursday afternoon, the picture was no longer visible on Subway’s Facebook page, which has 19.8 million fans. A spokesman for Subway, which is based in Milford, Conn., did not comment on the photo but said the length of its sandwiches can vary slightly when its bread, which is baked at each Subway location, is not made to the chain’s exact specifications.

“We are reinforcing our policies and procedures in an effort to ensure our offerings are always consistent no matter which Subway restaurant you visit,” Subway said in an e-mailed statement.

The photograph — and the backlash — illustrates a challenge companies face with the growth of social media sites like Facebook, YouTube and Twitter. Before, someone in far flung local in Australia would not be able to cause such a stir. But the power of social media means that negative posts about a company can spread from small towns to locations around the world in seconds.

“People look for the gap between what companies say and what they give, and when they find the gap — be it a mile or an inch — they can now raise a flag and say, ‘Hey look at this,’ I caught you,” said Allen Adamson, managing director of branding firm Landor Associates in New York.

The Subway footlong scandal is just the latest in a string of such social media public relations headaches for big companies.

Last year, a Burger King employee posted a Twitter message or “tweet” with a picture of someone standing in sneakers on two tubs of uncovered lettuce. Domino’s Pizza employees posted a video on YouTube of workers defacing a pizza in 2009. And a KitchenAid employee in 2012 made a disparaging remark about President Obama using the official KitchenAid Twitter account.

The key to mitigating damage when a social media furor arises is speed and directness, said Adamson, the branding expert.

“In today’s market you have to be able to roll with the punches and be much more fluid, responsive and responsible than before,” he said.