In a fine dining restaurant, is it okay to take a picture of your food?
Most restaurants permit photos. The smarter ones encourage it. But there are some where its is strictly verboten.
These tend to be places that pride themselves on their creativity, and don't want competitors to see what they're doing (which is dumb, since all the competitors have to do is eat there).
One of those places is Enigma in Barcelona. It's the latest opening by the brothers who created El Bulli, which was considered the best restaurant in the world at the time. They want their guests to be surprised and intrigued by each course, as opposed to "doesn't look at all like the picture I saw online."
What you do with your phone is your business.
1.) You're not using the flash and distracting patrons
2.) You're not taking pictures of the patrons themselves
3.) You can also flip your switch to vibrate (if an iPhone) and it will silence the shutter sound
4.) You purchased the food, you can photograph it
5.) Aside from making a social faux pas with anyone else you're dining with, I'm sure if they know you're going to do it, they won't care about a phone being used at the table for 2–3 seconds
You're in the clear!