Yes, it’s a known issue. The devs are absolutely slammed with optimization issues, and this will probably get addressed at some point.
All the UI is doing is automatically making it a markdown link. You can do it yourself just by doing [!test_community@sopuli.xyz](https://sopuli.xyz/c/test_community)
That’s actually not how it works. Images are hosted by the instance the community is on. Other instances embed those images as links in the page. The image is downloaded from the original instance by the browser.