I think if it's really privacy focussed then it's a really cool thing. But how can I be sure that the server is not storing my images and is completely private and confidential
Good question. You can actually verify it: after the page loads, you can go fully offline and all features still work. That’s because everything runs locally in the browser, and there are no image uploads. If you check DevTools → Network while editing, you shouldn’t see any file POSTs either.