Very nice, a couple of things you could improve:

- Mention that the image processing is done in the browser (and therefore works offline), which is great for privacy.

- Memorise the settings from one session to the next, via localStorage, or in the URL with `nuqs` (disclaimer: I'm the author).

- Your links in /about (cobalt.tools and your personal domain) don't work.

- You might want to set the html,body background colour to black, to avoid flashes of white background in weird viewport sizes and when overscrolling.