How to redirect a request/upload of an image to another application locally?

Question

Node.js

There are 2 Node applications on the server: one looks into the world and receives external requests, the second application works locally, on a different port.
When loading a picture, I want not to process it with the first application, but redirect it to the second, locally, and then, upon completion, receive the result and give it to the client.
On the first application, a regular Express server. On the second Express + Multer.
How to implement it? Only a local request to another port comes to mind where the second application is, for example via requestor axios, but will this be effective? Also what to transfer - completely somehow all request, or the buffer with a picture? Do I need Multer in the first application?