This is completely wrong. For example, you can increase the amount of oil or butter in a recipe, doubling or tripling its calorie count, and you would never be able to tell from a picture.
You'd have to be kind of stupid to expect it to actually be 100% accurate for all meals
4. I don't need this app.
Without knowing the amount of sugar, butter, oil, etc. is used in a dish, one cannot know if a dish is worth 250 kilocalories or 750 kilocalories.
If I need to manually fill in details of ingredients and amounts to get to the calories to be have an error margin of less than 100%, then the app is not useful and is at best misleading.