Heston Misses The Point

It depends on several factors:

1 Does the taking of the photo annoy other diners?

2 Does the taking of the photo delay/cause problems for the staff?

3 What is the reason for taking photo (eg you write food blogs, or you think it was great/awful and want to tell others)?

If 1 and 2 are not an issue, and the reason for taking the photo is not to show off, then I don't see a problem.

The real problem for restaurants is the use by diners of mobiles for social media when eating etc. 

A long established New York restaurant wondered why its serving times/table turnover had slowed down. They realised that since the advent of the mobile phone people were spending time looking at facebook etc, instead of ordering/eating the food. Hence delays in serving and table turnover. 

Photographing the food is not the problem, reading emails etc is the issue!