Some of these food delivery apps offer customers discounts if they upload high quality photos of individual food items so that they can be added to the menu in the app. For example, here’s DoorDash’s policy: https://help.doordash.com/en-us/consumers/article/photo-incentives-faq

I suspect what happened here is that the restaurant didn’t upload any of these photos. The real photos came from customers. But some items didn’t have high quality photos from customers yet, so the app uses AI ones instead.