A stock photo under a brand name is a lie
Finding a decent photograph of "beef burger" is easy and fair. Finding one for Diet Coke, or a named champagne, is neither — so the honest answer is to refuse.
Menu photographs sell food. That is not controversial and the data is not subtle. So a system that can find a decent, properly licensed photograph of a dish by its name is doing something useful for a kitchen with two hundred items and no photographer.
It also has to know when to stop.
Where a generic picture is fine
"Beef burger" describes a category of object. A well-lit photograph of a beef burger, freely licensed for commercial use, put on a menu next to the words beef burger, tells a customer roughly the truth: this is a burger, it is that sort of size, it comes in a bun. Nobody is deceived.
Where it stops being fine
"Diet Coke" does not describe a category. It names one company's product. A stock photograph of some other cola in a generic glass, sitting under those two words, tells a customer something untrue about what they are buying — and it does it in a way that looks entirely convincing.
The same goes further up the shelf than people expect. Our own bar has over a hundred lines with no photograph, and almost every one is a named thing: particular breweries, particular ciders, a named rosé, a named champagne, a named cognac. A picture of a rosé under the name of that rosé is not a helpful placeholder. It is a small fiction on a menu.
So it refuses, and says why
Branded products do not get a stock search. The screen says so in words rather than silently doing nothing: this is a branded product, so we do not go looking for a picture of it — upload the real one, or leave it without.
Leaving it without a photograph is a genuine option, and worth defending. A dish with no picture is a menu that has not finished. A dish with the wrong picture is a menu that is lying, and the customer cannot tell which one they are looking at.