I had to pull a few tricks to get it working. Discourse only renders a URL as an image if it ends in a picture extension like .jpg or .png. I had to put a hidden string at the end of the LaTeX so Discourse would detect it. I also had to do some manual URL encoding since Discourse has some bugs in the way it detects URLs. All in all, it’s not yet worth it. I’m trying to get the board to support the MathJax plugin, which would give native support, but with the admin side of things still in chaos I doubt it’ll happen soon.