Is there a term for "symbolic photo" (German "Symbolfoto")?

In German there is the term Symbolfoto or Symbolbild. It describes a photographic picture that represents a concept by means of abstraction or indirection.

A Symbolfoto could be a picture of food package contents prepared in a particular way — a serving suggestion therefore is a special type of Symbolfoto. Or it could be used in news articles, e.g. showing a picture of a traffic jam in an article describing holiday traffic — without actually depicting an actual traffic jam that the article might talk about.

In other contexts, Symbolfotos can be used for satirical or humorous purposes. For instance, a picture showing a ski slope with artificial snow surrounded by dried out mountain ranges in the middle of autumn could be seen as a Symbolfoto for the climate crisis and human desire to ignore it. There are many posts on German social media captioning images with “Symbolfoto”, thus giving the picture a new meaning.

There is a thread discussing this on a dictionary forum, but it is unresolved.

Is there any term or idiom for this in English?

The German language is fond of gluing nouns together to form new nouns that are distinct from the whole of their parts. English does have "symbol"(/symbolic) and "photo," and often simply calling it a "symbolic photo" might be the most direct solution.

However, there are some terms that are appropriate in specific situations:

• One of the most literally symbolic kinds of image is an icon. The oldest meaning is of a religiously significant image, but its use in computing is familiar, from an image that represents an application to a broad usage indicating any small image within an application that represents an idea or action, or can be interacted with.
• To the idea of an image of "a" traffic jam to represent "all" traffic jams: This is probably a stock photo. The term doesn't, in itself, address the idea of conceptual representation, but refers to photographs that are made available, usually in large libraries with certain licenses, for generic use. By extension it can refer to the practice of using generic images for specific uses (e.g. a gym shows a smiling person on a treadmill, not necessarily a real user of that specific gym).
• An image in which elements stand for other things allegorically, as is common in political cartoons, could be called a visual metaphor.
• Simple images, pictograms, with standardized meanings (like those for restrooms, wheelchair access, etc) might simply be called symbols.

Your question and examples not accord at all with the linked thread (in German) in which a "Symbolfoto" is used in place of another photograph in a case where (i) showing the identity of a person (or place) would be dangerous or illegal or (ii) to fill a space in the newspaper/on TV when a photo of the real incident does not exist.

Such photographs are known as "generic photos" or or marked "for illustration purposes only."

Use of these generic photos, in certain circumstances, usually comedy or satire, can lead to the photo being called a meme.

I would say in some cases you're referring to, this could be an icon. Or you might call something an "iconic image" to indicate that it represents its fundamental meaning.

In other cases you are describing, you might just call it an an illustration, which by its etymological definition "illuminates the meaning" or interprets something.

Finally, you refer to when the image replaces another, like in a new article. I agree with the other comment that "generic" or "stock" image is used.