It's really hard to tell what's in that picture. The volume is easy to see, though. I'll use a Mountain House dehydrated food bucket as reference. It holds sixteen packets. Depending on the level of activity, I'll estimate a grown man could survive on two packets per day. I'm estimating 14 buckets worth of stuff there. 14 buckets * 16 packets / 2 per day / 15 people on site = 7.5 days until they run out. I expect them to require more food than two packets per day. Backpacking I'd expect to have two of these, gummy bears (not the sugar free ones) and some summer sausage in a day. If they're active at all, my 7.5 day estimate will be very generous.
According to this article "It included a cardboard box of apples and oranges, a few dozen pots of instant ramen, 24 cans of chicken noodle soup, a similar number of cans of sweetcorn, peas, beans and chili, and 20 boxes of macaroni and cheese. There were also three sacks of potatoes, one bag of flour, another of rolled oats, boxes of raisins, a single bag of pretzels and one granola bar."