There are lots of great stock photos to be found online. Food and restaurants are not always a popular choice, but they are well-renowned among people in that niche. The stock photography website 123RF has a great collection of cooking photographs. These also include shots inside various restaurants and kitchens.
I have put together a brief gallery showcasing their works. Many of these photos were taken by freelance photographers who choose to sell their work online. It is notable how easily these sets may be put together, and the very affordable price tag even for non-subscribing members.