They also appreciate that diners share food photos as a way of showing their pleasure or disappointment. As pastry chef Gregoire Michaud, who has worked at top restaurants and hotels for 22 years, says: "Once you're on social media, you don't get to cherry-pick what you want to hear or see."

For some diners, the chef's image is of little concern. Australian foodie Peter Bailey feels free to photograph and share as he pleases. "It's my food to do with as I please. I'll shove it up my backside if I want to," Bailey says.

Some chefs in France have decided to regain control of their image. Alexandre Gauthier, chef at the Grenouillere restaurant in La Madelaine-sous-Montreuil, reportedly said that customers have switched from taking photos of their families to snapping the food, in some cases spending up to 10 minutes taking photos of it and allowing it to go cold.

The chef has complained of being quoted out of context, but his reported comments have reignited a debate about this most modern of restaurant etiquette issues.

Chefs contacted by the are mostly in favour of allowing customers to photograph their food, arguing that the guests have paid for it, so can do as they please. Chef Richard Ekkebus of Amber, and a friend of Gauthier, finds customers taking pictures of his food "the biggest form of flattery". He simply asks that diners respect a few of what he calls the "rules of engagement" and remember that a restaurant is not a photo studio.

It's a no-no for diners to stand on the chairs to get a better angle, or to set up tripods or monopods. Most crucial of all is to comply with the request not to use flash photography. The ban on flash photography is also highlighted when reservations are made.

Ekkebus says that customers always respond politely to such requests. The dislike of flash photography is because Ekkebus says it makes the restaurant's famous customers nervous, and can also faze guests such as businesspeople hoping to have discreet discussions.

Bjoern Alexander Panek, chef de cuisine at Whisk, says that food photography is a Hong Kong reality and the city's foodies take their photography very seriously. "Some of the pictures out there are of astonishing quality and definitely generate extra buzz," says Panek.

While he is aware "there is a sea of poor quality images" on social media, he doesn't think that is reason enough to ban the practice. He's not against wait staff pointing out to customers that certain dishes are best enjoyed hot.

For some chefs it's even worse when the camera-happy forget to take pictures until after they have started eating.

"Sometimes people forget to take the photos before they eat and then they photograph half-eaten dishes - these are actually the worst," says Franck Istel, executive pastry chef at the Opposite House in Beijing.

Michaud takes poor photography as a challenge to improve what he does rather than an insult. "If [customers] take a photo, I feel proud. If it looks stunning and the comments are great, I am happy.

If the photo is mediocre and the comments not so nice, I face it, and try to understand what could have possibly gone wrong and question my practice. Eventually, if I disagree with the comment, I will call the guest and discuss the issue in person."

Michaud also believes that if the food is good enough, poor photography can do no harm. "Roland Feuillas in France is a miller-extraordinaire, cultivating ancient grains, all organic, and using old-fashioned production and baking methods. He is highly active on Facebook, passing on his message to the young. If someone takes a poor photo with a low quality phone of his bread, it will still look awesome," he explains. The important point is to get the chef's message across.

For diners, the motives for taking photos are often far removed from any of the chefs' concerns. Ellen Wang Er-chong, an editor at Phoenix TV, says food porn is just an extension of the Chinese culture of sharing. "I think in Chinese culture we value the eating experience a lot," she says.

"We think it would be nice to show our friends the good food we've experienced. So, of course, after taking photos I upload them to social media networks."

Wang appreciates that the habit can annoy her dining partners, who have to wait for her to finish taking pictures before they can eat. Sometimes she even ends up taking pictures of perfectly ordinary food, a habit she is trying to break.

Stephy Poon Wing-ying, a media relations executive for a wine website, says that many of her friends share her food porn mania, so photo sessions at the dinner table don't bother them.

She is aware that flash photography can be annoying, so she doesn't use it. She usually takes photos of food when she feels dishes are worth sharing, for good or bad reasons. Her criteria are good presentation, impressive flavours, or some rare ingredients.

As with many other food photographers, she also uses the pictures to remember what she has eaten, and says they come in useful if she wants to try and recreate dishes at home.

In her experience, chefs welcome guests taking food photos. Perhaps that welcome exists because chefs are now as porn addled as their guests.

Ekkebus himself has been admonished by a chef in a Michelin three-star restaurant in Japan for asking to take a picture of him in his open kitchen. (The chef also said that Ekkebus' wife was eating too slowly.)

But Ekkebus says that although he didn't understand the practice when it first started, he is now "the first person to post pictures on Facebook or Instagram".

Joey Sergentakis, chef de cuisine at Café Gray Deluxe, is also a big fan of "camera eats first". "In a restaurant, you are inspired by the food, whether it is positive or negative. The presentation, composition and taste can all be inspiring.

"A guest has the right to remember the entire experience by photographing or videoing it," Sergentakis, says.

Or as Ekkebus puts it: "I'm the guiltiest right now of creating food porn."