How to redirect request to api if 404 for image?

Question

Nginx

The usual situation is nested folders (from parts of the name) to store pictures not in a bunch in the image folder , but in a structure like image/ab/cd/efg/abcdefg.png . There may not be a picture (thumbnail) in place, then it needs to be made from the original, and it has a different name.
The logic is simple: the API generates a picture and saves it in folders - after that the picture is available via a direct link. API available on different port and different URI
- Image URI: image/ab/cd/efg/abcdefg.png (port 80) -
URI of api method: image/abcdefg.png (port 8080)
processing in an API method?
PS: now it turns out to proxy the request unchanged through a named location. But you need to change the URI image/ ab/cd/efg/abcdefg.png -> image/abcdefg.png and throw out the folder structure from it.

Answer 1

I think something like this:

location /image/(.*\.png)$ {
    error_page 404 = http://127.0.0.1:8080/image/$1;
}

But it is not exactly...