You either didn't read the post, or you are taking their informal problem statement ("our frontend will call your endpoint [..]") WAY too literally. Hint: their frontend will NOT actually be calling your endpoint. They will probably never even run your endpoint once. It's just a way to describe where in the flow they want you to plug into.

They want an HTTP endpoint that takes a file over POST. Then they want an HTTP endpoint that returns the list of files over GET. They would also like basic things like a way to take an auth token to check if you have permission to upload, some unit testing, etc.

If you think this is anywhere even near to the ballpark of "actual work that they will use in their product", you're insane. This is basically 95% Django boilerplate that an experienced Django dev would be able to type out faster than it takes me to write this comment. To suggest that "write and read a .jpg" is somehow a part of their system that they're outsourcing (rather than the kind of thing you can find written out in dozens of Stack Overflow answers) is absurd.