How do I post a pic of my food in the app?

You have two options for posting your meals in the app.  Your first option is to open the nutrition section in the app and use the app camera to take a picture of your meal before you eat.  The app will stamp the time you took the picture as your meal time.  The other option you have is to take a picture of your meal before eating on your phone.  You can upload that photo at anytime and the app will time and date stamp it based on when the photo was taken. You cannot, however, use a photo that was taken on a different day or a different time than when you ate. It will not allow you to add a picture for a different date or time than when the picture was taken.