Food photography is insanely difficult: just like they say, "the camera adds 10 pounds", lighting and color differences between direct vision and photos make food look slightly off. Our brains are attuned from millions of years of evolution to see anything slightly off with our food to be gross. As a result, even food that looks delicious in person looks disgusting in photographs unless you're extremely careful to get the lighting just right. Professional photographs like this[1] are carefully lighted and highly edited, and even slight variations can make the lettuce look a bit off and the bun a bit burnt[2] or the pickles seem old and the cheese fake[3].

Long story short: people's low-res cell phone photos of half-eaten food taken under fluorescent lights basically indicate nothing about the food.

[1] https://www.mcdonalds.com/content/dam/usa/documents/newbigma...

[2] http://louiseroserailton.com/wp-content/uploads/2016/07/mcdo...

[3] http://i.dailymail.co.uk/i/pix/2012/07/10/article-2171302-13...