How to store pictures on a third-party service, but to view it was possible only from my site?

Question

Data storage

People will post pictures on the site and these pictures should not be visible outside the site.
Now I'm uploading all the images to imgur, is there any way to hide this fact and prevent people outside my site from seeing these photos, maybe not imgur but a similar service that provides an API for saving.
While the project is at the development stage, a large number of photos are expected in the future, I will start with cheap hosting rates (currently the cheapest on DigitalOcean) and increase as needed, so I want to store images not on my own.
Maybe this is generally the wrong approach, who faced, solved a similar problem, please explain.
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I read the term of use on imgur, it does not suit me at all.
suggest options for storing images

Answer 1

What you want is called "hotlinking protection".
There is a lot of information on this subject in search engines.
You can add the name of the web server you are using to the search phrase.