I have a web app where one could draw mandala designs.

I want the user to be able to eventually share that image to Facebook. I was able to convert the SVG element to base64, and to create a blob for the image, but then I don't know what's the best way to proceed.

It doesn't work if I pass it as an og:image meta tag when the user clicks the share button because the Facebook bot fetches the url as a new visitor, and therefore the image doesn't exist.

So what other solutions do I have? This is the app I mentioned