Serving dynamically generated files from GitHub Pages

Question

I'm a few months into web development so I apologize if I misunderstood anything.

What I did

I created a react-random-shapes package that would draw out random shapes as a React component. You can see an example here on my site or in the project page. Each time you refresh the page you'd get a new image. (Note: these pages use React.)

What I want to do next

The result I'm aiming for is to create an API (GET-only) on GitHub Pages that would return the dynamically generated svg file (so you can do something like

<img src="https://github.com/artt/react-random-shapes/blob?size=300&fill=red">

which would return a random blob for anyone who's interested in using. Alternatively, this API could return the svg path so the user could do whatever they want with it (e.g. animation).

The problem I have

Right now I know how to output an html page with the svg file, but not quite sure how to return just the svg (or json, etc.) part of it.

Thanks!